{"id":6723,"date":"2012-11-21T09:00:12","date_gmt":"2012-11-21T14:00:12","guid":{"rendered":"https:\/\/www.masterorganicchemistry.com\/?p=6723"},"modified":"2025-02-28T11:08:16","modified_gmt":"2025-02-28T17:08:16","slug":"deciding-sn1sn2e1e2-1-the-substrate","status":"publish","type":"post","link":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/","title":{"rendered":"Deciding SN1\/SN2\/E1\/E2 (1) &#8211; The Substrate"},"content":{"rendered":"<p><strong>The Role of The Substrate In Substitution &amp; Elimination Reaction: S<sub>N<\/sub>2 vs E1\/S<sub>N<\/sub>1\u00a0<\/strong><\/p>\n<ul>\n<li>Deciding whether a reaction is S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2 first of all requires understanding the bonds that form and break in each of these four reactions and the key features of their mechanisms (<em>Review here<\/em> &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/07\/13\/the-sn1-mechanism\/\">SN1<\/a> \/ <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/07\/04\/the-sn2-mechanism\/\">SN2<\/a> \/ <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/19\/the-e1-reaction\/\">E1<\/a> \/ <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/27\/the-e2-mechanism\/\">E2<\/a>)<\/li>\n<li>Primary, secondary, tertiary (and methyl) carbons attached to good leaving groups (such as alkyl halides and sulfonates) are good substrates for S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2 reactions. If this is not clear, <a href=\"https:\/\/www.masterorganicchemistry.com\/2023\/01\/18\/where-will-substitution-elimination-reactions-occur\/\"><strong>review here<\/strong><\/a><\/li>\n<li>If the alkyl carbon is <strong>primary<\/strong>, the lack of steric hindrance makes <strong>S<sub>N<\/sub>2 likely<\/strong> and the lack of carbocation stability makes S<sub>N<\/sub>1 and E1 unlikely.\u00a0 The main exception is with strong, bulky bases (E2).<\/li>\n<li>If the alkyl carbon is <strong>tertiary<\/strong>, it will <strong>not<\/strong> be <strong>S<sub>N<\/sub>2<\/strong>. More information is required to determine exactly which reaction will happen. Depending on the identity of the base (strong or weak) it may be S<sub>N<\/sub>1\/E1 (weak base) or E2 (strong base)<\/li>\n<li>Secondary alkyl halides can potentially undergo all four reactions and require analyzing the nucleophile \/ base. (<a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/30\/deciding-sn1sn2e1e2-2-the-nucleophilebase\/\"><em>See here<\/em><\/a>) as well as possibly the solvent and temperature.<\/li>\n<li>Alcohols can also be substrates for S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2 reactions, but require acidic conditions to convert OH into a good leaving group (OH<sub>2<\/sub><sup>+\u00a0<\/sup>). Basic conditions convert alcohols into alkoxides (RO<sup>&#8211;\u00a0<\/sup>) which are good nucleophiles.<\/li>\n<\/ul>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignnone wp-image-34269\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\" alt=\"summary- sn1 sn2 e1 e2 - substrate primary secondary tertiary\" width=\"640\" height=\"601\" \/><\/a><\/p>\n<p><strong>Table of Contents<\/strong><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li><a href=\"#one\">Step One: Determine If The Substrate is Primary, Secondary, or Tertiary<\/a><\/li>\n<li><a href=\"#two\">Let&#8217;s Look At Some Example Reactions<\/a><\/li>\n<li><a href=\"#three\">So The Substrate is Primary. Now What?<\/a><\/li>\n<li><a href=\"#four\">What if It&#8217;s Tertiary?\u00a0<\/a><\/li>\n<li><a href=\"#five\">The Problem Child: Secondary Alkyl Halides<\/a><\/li>\n<li><a href=\"#six\">A Look Ahead &#8211; Evaluating Nucleophile\/Base, Solvent, Temperature<\/a><\/li>\n<li><a href=\"#seven\">Some Examples With Alcohols<\/a><\/li>\n<li><a href=\"#eight\">Summary<\/a><\/li>\n<li><a href=\"#notes\">Notes<\/a><\/li>\n<li><a href=\"#quiz\">Quiz Yourself!<\/a><\/li>\n<li><a href=\"#references\">(Advanced) References and Further Reading<\/a><\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<hr \/>\n<h2><a id=\"one\"><\/a>1. First Off: Determine If The Substrate Is Primary, Secondary or Tertiary<\/h2>\n<p>What&#8217;s the very first step in deciding whether a reaction goes through S<sub>N<\/sub>1, S<sub>N<\/sub>2, E1 or E2?<\/p>\n<ul>\n<li>The very first thing is to identify a <strong>good leaving group<\/strong> such as Cl, Br, I, or OTs\/OMs! (<span style=\"color: #993366;\"><em>For a refresher, see this previous post &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2023\/01\/18\/where-will-substitution-elimination-reactions-occur\/\">How To Tell Where Substitution and Elimination Reactions Will Happen<\/a><\/em><\/span>)<\/li>\n<li>The other key thing to note is that with very few exceptions, substitution and elimination reactions <strong>only\u00a0<\/strong>happen on <strong>alkyl<\/strong> (i.e. sp<sup>3<\/sup>-hybridized) carbons.<\/li>\n<\/ul>\n<p>So for our purposes, in order for SN1\/SN2\/E1\/E2 to take place, we generally need to see\u00a0 an <strong>alkyl halide <\/strong>(<span style=\"color: #993366;\"><em>or alkyl sulfonates, such as tosylates and mesylates &#8211; See po<span style=\"color: #993366;\">st: <a style=\"color: #993366;\" href=\"https:\/\/www.masterorganicchemistry.com\/2015\/03\/10\/tosylates-and-mesylates\/\">Tosylates and Mesylates<\/a><\/span><\/em><\/span>).<\/p>\n<p>Once you&#8217;ve identified an alkyl halide, the next step is to determine whether it is <strong>primary<\/strong>, <strong>secondary<\/strong>, or <strong>tertiary<\/strong>.<\/p>\n<p>Try it for yourself with this quick quiz!<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34771\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34771\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34771\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34771\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34771\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34771 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34771\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-h2wrv\" data-id=\"h2wrv\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2466-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2466-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>If these are difficult for you, then back up and have another look at this post (<span style=\"color: #993366;\"><em>See article &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2010\/06\/16\/1-2-3-4\/\">Primary, Secondary, Tertiary, Quaternary in Organic Chemistry<\/a><\/em><\/span>)<\/p>\n<p>If this is too easy, then here&#8217;s a\u00a0\u00a0(slightly) more difficult set.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34788\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34788\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34788\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34788\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34788\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34788 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34788\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-1dcrh\" data-id=\"1dcrh\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2467-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2467-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>Note that sometimes these reactions are drawn out with reactions that won&#8217;t work. with the intention to test your understanding of mechanisms. If you see a question involving an alkenyl halide, your job is to figure out if it is put in there as a trick question, or if it qualifies as one of the (rare) exceptions to the &#8220;only alkyl carbons&#8221; rule. (<span style=\"color: #993366;\"><em>The main exception is formation of alkynes via double elimination &#8211; see <span style=\"color: #993366;\"><a style=\"color: #993366;\" href=\"https:\/\/www.masterorganicchemistry.com\/2013\/06\/11\/alkynes-via-elimination-reactions\/\">article<\/a><\/span><\/em><\/span>)<\/p>\n<h2><strong><a id=\"two\"><\/a>2. Looking At Some Reactions<\/strong><\/h2>\n<p>Once you can classify alkyl halides as primary, secondary, tertiary (or methyl!) the next step is to do it in the context of several\u00a0<strong>reactions<\/strong>, where it&#8217;s not uncommon to see things drawn up a little unconventionally.<\/p>\n<p>Before asking any other questions, look at the reactions below and see if you can identify potential\u00a0<strong>substrates<\/strong> for S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2 reactions.<\/p>\n<p>Let&#8217;s start with a fairly easy one. Identify primary, secondary, and tertiary:<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34773\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34773\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34773\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34773\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34773\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34773 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34773\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-765l5\" data-id=\"765l5\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2468-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2468-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>This one is slightly more difficult.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34774\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34774\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34774\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34774\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34774\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34774 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34774\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-6jhvj\" data-id=\"6jhvj\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2469-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2469-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>Finally, this has some harder examples.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34775\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34775\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34775\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34775\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34775\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34775 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34775\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-uhqb0\" data-id=\"uhqb0\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2470-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2470-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>If you&#8217;ve looked at the reaction and found a primary, secondary, tertiary or methyl halide (<em><span style=\"color: #993366;\">or tosylate\/mesylate, but<\/span> <strong>not\u00a0<\/strong>fluoride)<\/em>, then you are potentially looking at a substitution or elimination reaction.<\/p>\n<p>If there&#8217;s no alkyl halide, then it&#8217;s very likely there&#8217;s no substitution or elimination reaction!<\/p>\n<h2><a id=\"three\"><\/a>3. So The Alkyl Halide Is Primary &#8211; Now What?<\/h2>\n<p>All right. Let&#8217;s say we&#8217;ve identified our alkyl halide as\u00a0<strong>primary<\/strong>.<\/p>\n<p>Now what do we do?<\/p>\n<p>We can make a confident prediction. When the substrate is\u00a0<strong>primary<\/strong> (or methyl),\u00a0<strong>expect S<sub>N<\/sub>2<\/strong><\/p>\n<p>These reactions will almost certainly <strong>not\u00a0<\/strong>be S<sub>N<\/sub>1 or E1. [<a href=\"#noteone\"><span style=\"color: #ff0000;\">Note 1<\/span><\/a>] That&#8217;s because the first step of S<sub>N<\/sub>1\/E1 is loss of a leaving group to form a carbocation, and primary carbocations tend to be <strong>unstable<\/strong>. (<span style=\"color: #993366;\"><em>See article: <a style=\"color: #993366;\" href=\"https:\/\/www.masterorganicchemistry.com\/2011\/03\/11\/3-factors-that-stabilize-carbocations\/\">Carbocation Stability<\/a><\/em><\/span>)<\/p>\n<p>The next step is to predict the product. To do this, we:<\/p>\n<ul>\n<li>look for a good\u00a0<strong>nucleophile<\/strong>, then<\/li>\n<li>apply the <strong>key pattern<\/strong> for the S<sub>N<\/sub>2 reaction\u00a0 (form C-Nu, break C-LG)<\/li>\n<li><strong>invert<\/strong> the chiral center if there is one<span style=\"color: #993366;\"><em> (rare for primary)<\/em><\/span><\/li>\n<\/ul>\n<p><span style=\"color: #993366;\"><em>Also, it might help to recall the identities of common polar aprotic solvents such as DMF, DMSO, and acetonitrile (MeCN). These will affect the rate of substitution reactions but they are <strong>not<\/strong>\u00a0<strong>nucleophiles<\/strong><strong>.\u00a0<\/strong> (See article &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/04\/27\/polar-protic-polar-aprotic-nonpolar-all-about-solvents\/\">All About Solvents<\/a>)<\/em><\/span><\/p>\n<p>Now let&#8217;s put it into action. Assuming these reactions are S<sub>N<\/sub>2, <strong>draw the products<\/strong>.<\/p>\n<!-- quiz #34776 not found -->\n<p>These examples were meant to be straightforward. If you found that those examples of primary alkyl halides were too easy,\u00a0 then have a look at some of these trickier examples below.<span style=\"color: #993366;\"><em> (Not all of these will necessarily be S<sub>N<\/sub>2! )<\/em><\/span><\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34777\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34777\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34777\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34777\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34777\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34777 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34777\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-gg238\" data-id=\"gg238\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2472-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2472-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>Some additional things to note here:<\/p>\n<ul>\n<li>Alkyl <strong>fluorides<\/strong> do not generally undergo substitution or elimination reactions under normal conditions due to the strong C-F bond.<\/li>\n<li>Sodium hydride (NaH) is a strong <strong>base <\/strong>but a poor nucleophile. It doesn&#8217;t attack the carbon to displace a leaving group, but it will deprotonate alcohols to give alkoxides (RO(-) ) which <em>are<\/em> excellent nucleophiles. [<em><span style=\"color: #993366;\">Never forget &#8211; the conjugate base is always a better nucleophile!<\/span> <\/em>]<\/li>\n<li>There is only one situation where another reaction can compete with the S<sub>N<\/sub>2 on a primary alkyl halide, and that is when a\u00a0<strong>strong, bulky base\u00a0<\/strong>such as the\u00a0<em>t<\/em>-butoxide ion (e.g. <a href=\"https:\/\/www.masterorganicchemistry.com\/2011\/10\/29\/reagent-friday-kotbu\/\">KO<em>t<\/em>-Bu<\/a>) or lithium diisopropyl amide (<a href=\"https:\/\/www.masterorganicchemistry.com\/2011\/08\/05\/reagent-friday-lithium-di-isopropyl-amide-lda\/\">LDA<\/a>) is used. In these cases, the S<sub>N<\/sub>2 is slower than normal due to the steric bulk of the nucleophile, and elimination (E2) may start to compete with S<sub>N<\/sub>2.\u00a0 [<a href=\"#notetwo\"><span style=\"color: #ff0000;\">Note 2<\/span><\/a>]<\/li>\n<\/ul>\n<h2><a id=\"four\"><\/a>4. So The Alkyl Halide Is Tertiary &#8211; What Then?<\/h2>\n<p>Secondary alkyl halides are a bit thorny, so let&#8217;s skip them for a moment and move straight to tertiary.<\/p>\n<p>If the substrate is <strong>tertiary<\/strong>, you can <strong>rule out S<sub>N<\/sub>2<\/strong>. Why?<\/p>\n<p>S<sub>N<\/sub>2 reactions generally don&#8217;t happen on tertiary alkyl halides because the S<sub>N<\/sub>2 proceeds through a backside attack (<span style=\"color: #993366;\"><em>to the C-LG sigma* orbital<\/em><\/span>) , and the backside of tertiary alkyl halides is too sterically hindered for S<sub>N<\/sub>2 reactions to occur at any meaningful rate. (<span style=\"color: #993366;\"><em>See post &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2011\/07\/18\/steric-hindrance-is-like-a-fat-goalie\/\">Steric Hindrance is Like a Fat Goalie<\/a><\/em><\/span>)<\/p>\n<p>Since S<sub>N<\/sub>2 is out of the picture, we&#8217;re left trying to choose between S<sub>N<\/sub>1, E1, and E2.<\/p>\n<p><img decoding=\"async\" class=\"alignnone wp-image-34252\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/8-tertiary-substrates-generally-are-e2-with-strong-base-or-sn1-with-weak-base-e1-with-weak-base-and-heat.gif\" alt=\"tertiary substrates generally are e2 with strong base or sn1 with weak base e1 with weak base and heat\" width=\"640\" height=\"564\" \/><\/a><\/p>\n<p>So what then?<\/p>\n<p>I will cover this in the following article, but I don&#8217;t think I&#8217;m spoiling anything by saying that the next step is to <strong>look for the presence of a good base<\/strong>.\u00a0 [<span style=\"color: #993366;\"><em>See next article &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/30\/deciding-sn1sn2e1e2-2-the-nucleophilebase\/\">Deciding SN1\/SN2\/E1\/E2 &#8211; The Nucleophile \/Base<\/a><\/em><\/span>]<\/p>\n<p>By &#8220;good base&#8221;, I generally mean charged species at least\u00a0 as basic as alkoxides (RO<sup>\u2013<\/sup>\u00a0 ) or greater. [<span style=\"color: #993366;\"><em>although I would also include tertiary amines<\/em><\/span> <a href=\"#notethree\"><span style=\"color: #ff0000;\">Note 3<\/span><\/a> ]<\/p>\n<p>Seeing &#8220;heat&#8221; or the delta symbol &#8221; \u0394&#8221;\u00a0 is also a good clue that elimination is going on. [<span style=\"color: #993366;\"><em>See article &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/10\/elimination-reactions-are-favored-by-heat\/\">Elimination Reactions Are Favored By Heat<\/a><\/em><\/span>]<\/p>\n<p>In the <em>absence<\/em> of a strong base, expect <strong>S<sub>N<\/sub>1\/E1\u00a0<\/strong>with tertiary alkyl halides.<\/p>\n<p>That just opens up another question, of course.\u00a0 \u00a0How do you tell the difference between S<sub>N<\/sub>1 or E1?<\/p>\n<p>This will also be covered in another subsequent article (<span style=\"color: #993366;\"><em>See article &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/12\/19\/deciding-sn1sn2e1e2-4-the-temperature\/\">Deciding SN1\/SN2\/E1.E2 &#8211; The Role of Temperature<\/a><\/em><\/span>), but the short answer is, &#8220;<strong>heat<\/strong>&#8220;. If <strong>heat <\/strong>is applied, then expect the reaction to be E1.<\/p>\n<p>In the quiz below, which is collected from the examples above, I&#8217;ve actually done the work of identifying the most likely reaction pathway. Your job is to just draw the products.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34778\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34778\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34778\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34778\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34778\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34778 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34778\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-k9ugr\" data-id=\"k9ugr\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2473-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2473-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>See this <a href=\"#notefour\"><span style=\"color: #ff0000;\">Note 4<\/span><\/a> for the slightly more difficult example.<\/p>\n<h2><a id=\"five\"><\/a>5. It&#8217;s Secondary &#8211; Now What?<\/h2>\n<p>Finally we get to the &#8220;fun&#8221; part: secondary alkyl halides. (<span style=\"color: #993366;\"><em>Note &#8211; your definition of &#8220;fun&#8221; may vary<\/em><\/span>)<\/p>\n<p>The short news is that for secondary alkyl halides, we cant rule anything out. Depending on conditions, each of the four reaction patterns could potentially be observed.<\/p>\n<p>I&#8217;m not going to be able to summarize the whole range of possibilities in one paragraph, but the next key question will be to <strong>examine the identity of the base \/ nucleophile<\/strong>.<\/p>\n<p><img decoding=\"async\" class=\"alignnone wp-image-34253\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/10-secondary-alkyl-halides-can-each-give-sn1-sn2-e1-e2-depending-on-identity-of-nucleophile-base-negatively-charged-or-neutral.gif\" alt=\"secondary alkyl halides can each give sn1 sn2 e1 e2 depending on identity of nucleophile base - negatively charged or neutral\" width=\"640\" height=\"598\" \/><\/a><\/p>\n<ul>\n<li>Generally speaking, if the nucleophile\/base is &#8220;strong&#8221; (<span style=\"color: #993366;\"><em>and for our purposes, this means, &#8220;has a <strong>negative charge&#8221;<\/strong><\/em><\/span>) then\u00a0<strong>expect S<sub>N<\/sub>2<\/strong> or <strong>E2<\/strong><\/li>\n<li>If the nucleophile\/base is &#8220;weak&#8221; (neutral, for our purposes) then expect <strong>S<sub>N<\/sub>1\u00a0\/ E1.<\/strong><\/li>\n<\/ul>\n<p>Distinguishing S<sub>N<\/sub>2 vs E2 on a secondary alkyl halide is worth a whole other article on its own.<\/p>\n<p>For now, let&#8217;s\u00a0 just note that\u00a0 the E2 requires a strong base, whereas the S<sub>N<\/sub>2 requires a strong nucleophile.<\/p>\n<p>By &#8220;strong&#8221; I would suggest hydroxide ion (HO &#8211; , the conjugate base of water, pK<sub>a<\/sub> = 14) as a good cutoff point.<\/p>\n<ul>\n<li>Thiolates, the conjugate bases of thiols (pK<sub>a<\/sub> 10) tend to perform substitution reactions on secondary alkyl halides, as do less basic species such as N<sub>3<\/sub>(-), CN(-), halides, and carboxylates. (<span style=\"color: #993366;\"><em>For a good list of nucleophiles, see post &#8211; <a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/07\/11\/why-the-sn2-reaction-is-powerful\/\">Why The S<sub>N<\/sub>2 Is Powerful<\/a><\/em><\/span>)<\/li>\n<li>Ssecondary alkyl halides treated with alkoxides are a particularly tricky case, as this is the borderline region between S<sub>N<\/sub>2 and E2. For a good time, <strong>ask your instructor<\/strong> on what <em>they<\/em> think will happen. (<em><span style=\"color: #993366;\">My personal observation is that polar aprotic solvents such as DMSO, DMF, and acetonitrile indicate S<sub>N<\/sub>2 whereas polar protic solvents indicate E2, but there are exceptions<\/span>).\u00a0<\/em><\/li>\n<li>Nucleophiles that are more basic than alkoxides tend to give E2 with secondary alkyl halides. Acetylides, the conjugate bases of terminal alkynes are a classic example here. [<a href=\"#notefive\"><span style=\"color: #ff0000;\">Note 5<\/span><\/a>]<\/li>\n<\/ul>\n<p>Here are some of the simpler examples from above. The more complex ones I&#8217;ll cover in the notes below.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"34779\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34779\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34779\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34779\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34779\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34779 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34779\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-c2v73\" data-id=\"c2v73\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2474-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2474-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>I&#8217;ll handle some of the more complicated cases of secondary alkyl halides in the notes below.<\/p>\n<h2><a id=\"six\"><\/a>6. A Look Ahead<\/h2>\n<p>Although this is intended to be just one article in a sequence that walk through the process of deciding SN1\/SN2\/E1\/E2, I appreciate that not everyone will go through this sequentially.<\/p>\n<p>This is an outline of the thought process:<\/p>\n<ul>\n<li>The role of the substrate (<strong>this article<\/strong>)<\/li>\n<li>The role of the nucleophile\/base (<em><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/30\/deciding-sn1sn2e1e2-2-the-nucleophilebase\/\">next<\/a>! <\/em>)<\/li>\n<li>The role of the solvent (<a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/12\/04\/deciding-sn1sn2e1e2-the-solvent\/\"><em>S<sub>N<\/sub>2 vs E2 with secondary alkyl halides<\/em><\/a>)<\/li>\n<li>The role of temperature (<a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/12\/19\/deciding-sn1sn2e1e2-4-the-temperature\/\"><em>S<sub>N<\/sub>1 vs E1<\/em><\/a>)<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-34254\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/12-understanding-the-thought-process-for-deciding-if-a-reaction-is-sn1-sn2-e1-e2.gif\" alt=\"understanding the thought process for deciding if a reaction is sn1 sn2 e1 e2\" width=\"640\" height=\"531\" \/><\/a><\/p>\n<h2><a id=\"seven\"><\/a>7. Some Examples With Alcohols<\/h2>\n<p>We&#8217;ve been talking about reactions of alkyl halides, but these reactions can happen with <strong>alcohols<\/strong> as well.<\/p>\n<p>In their neutral form alcohols are poor nucleophiles and are also poor substrates for S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2 reactions since the hydroxide group (HO<sup>&#8211;<\/sup>) is a poor leaving group.<\/p>\n<p>However, adding an <strong>acid<\/strong> or a\u00a0<strong>base<\/strong> can change the alcohol&#8217;s personality dramatically!<\/p>\n<ul>\n<li>Treating an alcohol with a\u00a0<strong>base\u00a0<\/strong>makes the alcohol into an alkoxide, which is a far better <strong>nucleophile<\/strong> than a neutral alcohol.<\/li>\n<li>Treating an alcohol with an\u00a0<strong>acid<\/strong> protonates the hydroxyl group R\u2013OH into R\u2013OH<sub>2<\/sub>(+)\u00a0which is a far better leaving group than HO(-). This means that protonated alcohols can be electrophiles in S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1 reactions <em>(<span style=\"color: #993366;\">but generally not E2, since strong acids aren&#8217;t compatible with strong bases!<\/span>)\u00a0<\/em><\/li>\n<\/ul>\n<div class=\"wq-quiz-wrapper\" data-id=\"34780\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"34780\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"34780\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"34780\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-34780\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-34780 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"34780\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-jcchn\" data-id=\"jcchn\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2475-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2475-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p>More on the substitution and elimination reactions of alcohols in the alcohol chapter. (<a href=\"https:\/\/www.masterorganicchemistry.com\/2014\/10\/06\/how-to-make-alcohols-more-reactive\/\"><em>Start here<\/em><\/a>, for example)<\/p>\n<h2><a id=\"eight\"><\/a>8. Summary<\/h2>\n<ul>\n<li>Identifying the type of substrate (primary, secondary, tertiary or methyl halide) is the first step towards identifying a reaction as S<sub>N<\/sub>1\/S<sub>N<\/sub>2\/E1\/E2.<\/li>\n<li>I personally find it more helpful to look at it from the perspective of\u00a0<em>ruling things out\u00a0<\/em>rather than the inverse.<\/li>\n<li>If the alkyl halide is primary, you can rule out SN1 and E1, and rule out E2 unless the nucleophile is a very bulky base.<\/li>\n<li>If the alkyl halide is tertiary, you can rule out SN2.<\/li>\n<\/ul>\n<p>With secondary alkyl halides, you can&#8217;t rule out any pathway in some cases without looking at the nucleophile\/base.<\/p>\n<p>That&#8217;s next!<\/p>\n<hr \/>\n<h2><strong><a id=\"notes\"><\/a>Notes<\/strong><\/h2>\n<div class=\"related-articles\"><p><strong>Related Articles<\/strong><\/p><ul><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/30\/deciding-sn1sn2e1e2-2-the-nucleophilebase\/\" class=\"\"><span>Deciding SN1\/SN2\/E1\/E2 (2) \u2013 The Nucleophile\/Base<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2023\/01\/18\/where-will-substitution-elimination-reactions-occur\/\" class=\"\"><span>Identifying Where Substitution and Elimination Reactions Happen<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/12\/19\/sn1-vs-e1-temperature-sn2-vs-e2\/\" class=\"\"><span>SN1 vs E1 and SN2 vs E2 : The Temperature<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/07\/13\/the-sn1-mechanism\/\" class=\"\"><span>The SN1 Mechanism<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/07\/04\/the-sn2-mechanism\/\" class=\"\"><span>The SN2 Mechanism<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/19\/the-e1-reaction\/\" class=\"\"><span>The E1 Reaction<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/27\/the-e2-mechanism\/\" class=\"\"><span>The E2 Mechanism<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2011\/03\/11\/3-factors-that-stabilize-carbocations\/\" class=\"\"><span>3 Factors That Stabilize Carbocations<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2011\/04\/12\/what-makes-a-good-leaving-group\/\" class=\"\"><span>What makes a good leaving group?<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2010\/06\/16\/1-2-3-4\/\" class=\"\"><span>Primary, Secondary, Tertiary, Quaternary In Organic Chemistry<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/organic-chemistry-practice-problems\/sn1-sn2-e1-e2-practice-problems\/\" class=\"\"><span>SN1 SN2 E1 E2 Practice Problems (MOC Membership)<\/span><\/a><\/li><\/ul><\/div>\n<p><strong><a id=\"noteone\"><\/a>Note 1.\u00a0\u00a0<\/strong>It is also possible for the S<sub>N<\/sub>1 pathway to operate with primary\u00a0<em>allylic<\/em> halides that are capable of forming extremely stable carbocations, particularly in very polar solvents such as mixtures of water and ethanol or formic acid.<\/p>\n<p>One classic example is gamma, gamma dimethylallyl chloride, where the SN1 pathway is dominant.<\/p>\n<div class=\"wq-quiz-wrapper\" data-id=\"35007\"><style type=\"text\/css\" id=\"wq-flip-custom-css\">.wq-quiz-wrapper[data-id=\"35007\"] {\n--wq-question-width: 100%;\n--wq-question-color: #009cff;\n--wq-question-height: auto;\n--wq-font-color: #444;\n}\n\n\t\t\t.wq-quiz-wrapper[data-id=\"35007\"] {\n\t\t\t\t--wq-question-width: 600px;\n\t\t\t}\n\n\t\t\t@media screen and (max-width: 600px) {\n\t\t\t\t.wq-quiz-wrapper[data-id=\"35007\"] .wq_singleQuestionWrapper { width:100% !important; height:auto !important; }\n\t\t\t}\n\t\t<\/style><!-- wp quiz -->\n<div id=\"wp-quiz-35007\" class=\"wq_quizCtr single flip_quiz wq-quiz wq-quiz-35007 wq-quiz-flip wq-layout-single wq-skin-traditional wq-should-show-correct-answer\" data-quiz-id=\"35007\">\n<div class=\"wq-questions wq_questionsCtr\">\n\t<div class=\"wq-question wq_singleQuestionWrapper wq-question-qm51z\" data-id=\"qm51z\">\n\n\t\n\t<div class=\"item_top\">\n\t\t<div class=\"title_container\">\n\t\t\t<div class=\"wq_questionTextCtr\">\n\t\t\t\t<h4 class=\"wq-question-title\"><\/h4>\n\t\t\t<\/div>\n\t\t<\/div>\n\t<\/div>\n\n\t<div class=\"card \">\n\t\t<div class=\"front\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2513-Front.gif\" \/>\n\t\t\n\t\t\n\t\n\t\n\t\t\t<span class=\"top-desc\">Click to Flip<\/span>\n\t<\/div>\n\t\t<div class=\"back\" >\n\t\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-images\/2513-Reverse.gif\" \/>\n\t\t\n\t\t\n\t\n\t<\/div>\n\t<\/div>\n\n\t\n<\/div>\n<\/div>\n<\/div>\n<!-- \/\/ wp quiz-->\n<\/div><!-- End .wq-quiz-wrapper -->\n<p><strong><a id=\"notetwo\"><\/a>Note 2. <\/strong>Note that\u00a0I&#8217;m not saying here that E2 will be the <em>exclusive (100%) <\/em>product, just that the percentage of E2 product will start to\u00a0<em>increase<\/em> relative to SN2. Mixtures of products are fairly common in organic chemistry.<\/p>\n<p><strong><a id=\"notethree\"><\/a>Note 3.\u00a0<\/strong>Tertiary amines (R<sub>3<\/sub>N) are one example of an exception to this rule of thumb, as they are neutral species yet competent bases.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-34602\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2012\/11\/F2-triethylamine-and-triphenylphospine-are-examples-of-neutral-species-that-are-good-nucleophiles-bases.gif\" alt=\"triethylamine and triphenylphospine are examples of neutral species that are good nucleophiles bases\" width=\"640\" height=\"327\" \/><\/a><\/p>\n<p>Phosphines (e.g. triphenylphosphine, PPh<sub>3<\/sub>) are poor bases but are excellent nucleophiles in S<sub>N<\/sub>2 reactions.<\/p>\n<p><strong><a id=\"notefour\"><\/a>Note 4.\u00a0<\/strong>If a carbocation is formed in the presence of a species that is a good nucleophile but a poor base, such as cyanide or azide ion, then these good nucleophiles can &#8220;intercept&#8221; the carbocation and react with it in place of the solvent.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-34603\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2012\/11\/F3-intercepting-carbocations-formed-under-sn1-conditions-with-external-nucleophiles-such-as-nan3.gif\" alt=\"-intercepting carbocations formed under sn1 conditions with external nucleophiles such as nan3\" width=\"640\" height=\"264\" \/><\/a><\/p>\n<p><strong><a id=\"notefive\"><\/a>Note 5.\u00a0<\/strong>When secondary alkyl halides are treated with acetylides, the major product tends to be\u00a0<strong>elimination\u00a0<\/strong>rather than substitution products.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-34604\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2012\/11\/F4-acetylide-ions-tend-to-perform-elimination-reactions-with-secondary-alkyl-halides-instead-of-substitution-sn2.gif\" alt=\"acetylide ions tend to perform elimination reactions with secondary alkyl halides instead of substitution sn2\" width=\"640\" height=\"423\" \/><\/a><\/p>\n<p>For examples, see this <a href=\"#refthree\">reference<\/a>.<\/p>\n<p><strong>Note 6. <\/strong>This is a handy table of relative rates for various alkyl halides in substitution reactions with halide ions.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-34605\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2012\/11\/F6-representative-table-of-relative-reactivities-of-alkyl-halides-according-to-Streitweiser.gif\" alt=\"representative table of relative reactivities of alkyl halides according to Streitweiser\" width=\"640\" height=\"733\" \/><\/a><\/p>\n<hr \/>\n<h2><strong><a id=\"quiz\"><\/a>Quiz Yourself!<\/strong><\/h2>\n\n<p class=\"p1\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26714\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-previews\/3113-Front-Image-Only.png\" alt=\"\" width=\"640\" height=\"616\" \/><\/p>\n<p><a href=\"https:\/\/www.masterorganicchemistry.com\/moc-membership\/\"><strong>Become a\u00a0 MOC member<\/strong><\/a> to see the clickable quiz with answers on the back. &nbsp;<br \/>\n<\/p>\n<p class=\"p1\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26714\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-previews\/3114-Front-Image-Only.png\" alt=\"\" width=\"640\" height=\"616\" \/><\/p>\n<p><a href=\"https:\/\/www.masterorganicchemistry.com\/moc-membership\/\"><strong>Become a\u00a0 MOC member<\/strong><\/a> to see the clickable quiz with answers on the back. <\/p>\n\n<p class=\"p1\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26714\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-previews\/2500-Front-Image-Only.png\" alt=\"\" width=\"640\" height=\"616\" \/><\/p>\n<p><a href=\"https:\/\/www.masterorganicchemistry.com\/moc-membership\/\"><strong>Become a\u00a0 MOC member<\/strong><\/a> to see the clickable quiz with answers on the back. <\/p>\n\n<p class=\"p1\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26714\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-previews\/2501-Front-Image-Only.png\" alt=\"\" width=\"640\" height=\"616\" \/><\/p>\n<p><a href=\"https:\/\/www.masterorganicchemistry.com\/moc-membership\/\"><strong>Become a\u00a0 MOC member<\/strong><\/a> to see the clickable quiz with answers on the back. <br \/>\n<\/p>\n<p class=\"p1\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-26714\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/quiz-previews\/2502-Front-Image-Only.png\" alt=\"\" width=\"640\" height=\"616\" \/><\/p>\n<p><a href=\"https:\/\/www.masterorganicchemistry.com\/moc-membership\/\"><strong>Become a\u00a0 MOC member<\/strong><\/a> to see the clickable quiz with answers on the back. <\/p>\n<hr \/>\n<h2><strong><a id=\"references\"><\/a>(Advanced) References and Further Reading<\/strong><\/h2>\n<p>One key reference for understanding the interplay between SN1\/SN2\/E1 and E2 reactions is an older, but very valuable review by Prof. Andrew Streitweiser (Berkeley) in &#8220;<a href=\"https:\/\/archive.org\/details\/solvolyticdispla0000andr_t6p6\">Solvolytic Displacement Reactions<\/a>&#8221; (McGraw-Hill, 1962, New York) which summarizes hundreds of publications on the subject prior to 1960. Most of the book is a republication of an earlier review by Streitweiser bearing the same title. (<a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/cr50010a001\"><em>Chemical Reviews, 1956, 56, 571<\/em><\/a>)<\/p>\n<ol>\n<li class=\"capsule__title fixpadv--m\"><strong>Kinetics and mechanisms of nucleophilic displacements in allylic systems. Part VIII. The reactivities of allylic chlorides towards bimolecular substitution without rearrangement<br \/>\n<\/strong>C. A. Vernon<br \/>\n<em><i>J. Chem. Soc.<\/i>, <\/em><strong>1954<\/strong>, 4462-4470<br \/>\n<strong>DOI: <\/strong>1<a class=\"text--small\" title=\"Link to landing page via DOI\" href=\"https:\/\/doi.org\/10.1039\/JR9540004462\">0.1039\/JR9540004462<\/a><\/li>\n<li>\n<p class=\"capsule__title fixpadv--m\"><strong>The kinetics and mechanisms of nucleophilic displacements in allylic systems. Part V. Reactivities of allylic halides by the\u00a0<em>S<\/em><sub>N<\/sub>1 mechanism of hydrolysis<br \/>\n<\/strong>C. A. Vernon<br \/>\n<i>J. Chem. Soc.<\/i>, <strong>1954<\/strong>, 423-428<br \/>\n<b>DOI: <\/b><a class=\"text--small\" title=\"Link to landing page via DOI\" href=\"https:\/\/doi.org\/10.1039\/JR9540000423\">10.1039\/JR9540000423<\/a><br \/>\nStudy on the SN1 pathway (solvolysis) for several <strong>primary<\/strong> allylic chlorides. The SN1 pathway for the hydrolysis gamma,gamma-dimethallyl chloride in formic acid is particularly significant, relative to allyl chloride.<\/p>\n<\/li>\n<li><strong><a id=\"refthree\"><\/a>Preparation of Alkynes and Dialkynes by Reaction of Monohalo- and Dihaloalkanes with Lithium Acetylenide-Ethylenediamine Complex<br \/>\n<\/strong>W.\u00a0Novis\u00a0SMITH<sup>*<\/sup>\u00a0, O.\u00a0F.\u00a0BEUMEL, Jr.<br \/>\n<em>Synthesis,<\/em>\u00a0<strong>1974<\/strong>, 441-443.<br \/>\n<strong>DOI<\/strong>: <a href=\"https:\/\/www.thieme-connect.com\/products\/ejournals\/abstract\/10.1055\/s-1974-23341\">10.1055\/s-1974-23341<\/a><br \/>\nStudy on the SN2 reaction of lithium acetylides with various primary alkyl halides (primary alkyl iodides and bromides are fast, primary alkyl chlorides are slow, secondary alkyl halides give elimination)<\/li>\n<li><strong>SN2 versus SN2\u2032 Competition<\/strong><br \/>\nThomas Hansen, Pascal Vermeeren, Lea de Jong, F. Matthias Bickelhaupt, and Trevor A. Hamlin<br \/>\n<em>The Journal of Organic Chemistry<\/em> <strong>2022<\/strong> 87 (14), 8892-8901<br \/>\n<strong>DOI<\/strong>: <a href=\"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.joc.2c00527\">10.1021\/acs.joc.2c00527<\/a><br \/>\nVery recent paper on SN2 (and SN2&#8242;) reactions of allyl halides with leading references.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>The Role of The Substrate In Substitution &amp; Elimination Reaction: SN2 vs E1\/SN1\u00a0 Deciding whether a reaction is SN1\/SN2\/E1\/E2 first of all requires understanding the <\/p>\n","protected":false},"author":1,"featured_media":34269,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1417],"tags":[472,473,201,502,271,279],"post_folder":[],"class_list":["post-6723","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-sn1sn2e1e2","tag-e1","tag-e2","tag-elimination","tag-sn1","tag-sn2","tag-substitution"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Deciding SN1\/SN2\/E1\/E2 (1) - The Substrate &#8211; Master Organic Chemistry<\/title>\n<meta name=\"description\" content=\"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Deciding SN1\/SN2\/E1\/E2 (1) - The Substrate &#8211; Master Organic Chemistry\" \/>\n<meta property=\"og:description\" content=\"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/\" \/>\n<meta property=\"og:site_name\" content=\"Master Organic Chemistry\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/Master-Organic-Chemistry-242610599108055\/\" \/>\n<meta property=\"article:published_time\" content=\"2012-11-21T14:00:12+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-02-28T17:08:16+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\" \/>\n\t<meta property=\"og:image:width\" content=\"884\" \/>\n\t<meta property=\"og:image:height\" content=\"830\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/gif\" \/>\n<meta name=\"author\" content=\"James Ashenhurst\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"James Ashenhurst\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"15 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/\"},\"author\":{\"name\":\"James Ashenhurst\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#\\\/schema\\\/person\\\/78d83ec7d02b4b7365bade2cedaef80c\"},\"headline\":\"Deciding SN1\\\/SN2\\\/E1\\\/E2 (1) &#8211; The Substrate\",\"datePublished\":\"2012-11-21T14:00:12+00:00\",\"dateModified\":\"2025-02-28T17:08:16+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/\"},\"wordCount\":2723,\"commentCount\":49,\"publisher\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2023\\\/02\\\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\",\"keywords\":[\"e1\",\"e2\",\"elimination\",\"sn1\",\"SN2\",\"substitution\"],\"articleSection\":[\"SN1\\\/SN2\\\/E1\\\/E2 Decision\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/\",\"name\":\"Deciding SN1\\\/SN2\\\/E1\\\/E2 (1) - The Substrate &#8211; Master Organic Chemistry\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2023\\\/02\\\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\",\"datePublished\":\"2012-11-21T14:00:12+00:00\",\"dateModified\":\"2025-02-28T17:08:16+00:00\",\"description\":\"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2023\\\/02\\\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\",\"contentUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2023\\\/02\\\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif\",\"width\":884,\"height\":830,\"caption\":\"summary- sn1 sn2 e1 e2 - substrate primary secondary tertiary\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2012\\\/11\\\/21\\\/deciding-sn1sn2e1e2-1-the-substrate\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Deciding SN1\\\/SN2\\\/E1\\\/E2 (1) &#8211; The Substrate\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#website\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/\",\"name\":\"Master Organic Chemistry\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#organization\",\"name\":\"Master Organic Chemistry\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/04\\\/cutmypic.png\",\"contentUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/04\\\/cutmypic.png\",\"width\":225,\"height\":225,\"caption\":\"Master Organic Chemistry\"},\"image\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.facebook.com\\\/Master-Organic-Chemistry-242610599108055\\\/\"]},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#\\\/schema\\\/person\\\/78d83ec7d02b4b7365bade2cedaef80c\",\"name\":\"James Ashenhurst\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g\",\"caption\":\"James Ashenhurst\"},\"description\":\"Ph.D. 2006, McGill University (James L. Gleason). Postdoctoral Associate, 2008-2010, Massachusetts Institute of Technology (M. Movassaghi). Founder, Master Organic Chemistry, 2010-present.\",\"sameAs\":[\"https:\\\/\\\/www.masterorganicchemistry.com\\\/about\\\/\"],\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/author\\\/james\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Deciding SN1\/SN2\/E1\/E2 (1) - The Substrate &#8211; Master Organic Chemistry","description":"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/","og_locale":"en_US","og_type":"article","og_title":"Deciding SN1\/SN2\/E1\/E2 (1) - The Substrate &#8211; Master Organic Chemistry","og_description":"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.","og_url":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/","og_site_name":"Master Organic Chemistry","article_publisher":"https:\/\/www.facebook.com\/Master-Organic-Chemistry-242610599108055\/","article_published_time":"2012-11-21T14:00:12+00:00","article_modified_time":"2025-02-28T17:08:16+00:00","og_image":[{"width":884,"height":830,"url":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif","type":"image\/gif"}],"author":"James Ashenhurst","twitter_card":"summary_large_image","twitter_misc":{"Written by":"James Ashenhurst","Est. reading time":"15 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#article","isPartOf":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/"},"author":{"name":"James Ashenhurst","@id":"https:\/\/www.masterorganicchemistry.com\/#\/schema\/person\/78d83ec7d02b4b7365bade2cedaef80c"},"headline":"Deciding SN1\/SN2\/E1\/E2 (1) &#8211; The Substrate","datePublished":"2012-11-21T14:00:12+00:00","dateModified":"2025-02-28T17:08:16+00:00","mainEntityOfPage":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/"},"wordCount":2723,"commentCount":49,"publisher":{"@id":"https:\/\/www.masterorganicchemistry.com\/#organization"},"image":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#primaryimage"},"thumbnailUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif","keywords":["e1","e2","elimination","sn1","SN2","substitution"],"articleSection":["SN1\/SN2\/E1\/E2 Decision"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/","url":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/","name":"Deciding SN1\/SN2\/E1\/E2 (1) - The Substrate &#8211; Master Organic Chemistry","isPartOf":{"@id":"https:\/\/www.masterorganicchemistry.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#primaryimage"},"image":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#primaryimage"},"thumbnailUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif","datePublished":"2012-11-21T14:00:12+00:00","dateModified":"2025-02-28T17:08:16+00:00","description":"SN1 SN2 E1 E2 : Substrate. The biggest impact on which reaction pathway occurs is whether the alkyl halide is primary, secondary, or tertiary.","breadcrumb":{"@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#primaryimage","url":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif","contentUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2023\/02\/0-summary-sn1-sn2-e1-e2-substrate-primary-secondary-tertiary.gif","width":884,"height":830,"caption":"summary- sn1 sn2 e1 e2 - substrate primary secondary tertiary"},{"@type":"BreadcrumbList","@id":"https:\/\/www.masterorganicchemistry.com\/2012\/11\/21\/deciding-sn1sn2e1e2-1-the-substrate\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.masterorganicchemistry.com\/"},{"@type":"ListItem","position":2,"name":"Deciding SN1\/SN2\/E1\/E2 (1) &#8211; The Substrate"}]},{"@type":"WebSite","@id":"https:\/\/www.masterorganicchemistry.com\/#website","url":"https:\/\/www.masterorganicchemistry.com\/","name":"Master Organic Chemistry","description":"","publisher":{"@id":"https:\/\/www.masterorganicchemistry.com\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.masterorganicchemistry.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.masterorganicchemistry.com\/#organization","name":"Master Organic Chemistry","url":"https:\/\/www.masterorganicchemistry.com\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.masterorganicchemistry.com\/#\/schema\/logo\/image\/","url":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/04\/cutmypic.png","contentUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/04\/cutmypic.png","width":225,"height":225,"caption":"Master Organic Chemistry"},"image":{"@id":"https:\/\/www.masterorganicchemistry.com\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/Master-Organic-Chemistry-242610599108055\/"]},{"@type":"Person","@id":"https:\/\/www.masterorganicchemistry.com\/#\/schema\/person\/78d83ec7d02b4b7365bade2cedaef80c","name":"James Ashenhurst","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/f9e9df435875e5e6b0bdff6b8522a7279d5717644b3efa7299da22c837bf9fcf?s=96&d=retro&r=g","caption":"James Ashenhurst"},"description":"Ph.D. 2006, McGill University (James L. Gleason). Postdoctoral Associate, 2008-2010, Massachusetts Institute of Technology (M. Movassaghi). Founder, Master Organic Chemistry, 2010-present.","sameAs":["https:\/\/www.masterorganicchemistry.com\/about\/"],"url":"https:\/\/www.masterorganicchemistry.com\/author\/james\/"}]}},"_links":{"self":[{"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/posts\/6723","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/comments?post=6723"}],"version-history":[{"count":0,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/posts\/6723\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/media\/34269"}],"wp:attachment":[{"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/media?parent=6723"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/categories?post=6723"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/tags?post=6723"},{"taxonomy":"post_folder","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/post_folder?post=6723"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}