{"id":11147,"date":"2017-11-09T14:32:53","date_gmt":"2017-11-09T19:32:53","guid":{"rendered":"https:\/\/www.masterorganicchemistry.com\/?p=11147"},"modified":"2025-02-28T12:10:09","modified_gmt":"2025-02-28T18:10:09","slug":"electrophilic-aromatic-substitution-the-mechanism","status":"publish","type":"post","link":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/","title":{"rendered":"Electrophilic Aromatic Substitution &#8211; The Mechanism"},"content":{"rendered":"<p><strong>Electrophilic Aromatic Substitution: The Mechanism<\/strong><\/p>\n<ul>\n<li><strong>Electrophilic aromatic substitution (EAS)<\/strong> reactions proceed through a <strong>two-step<\/strong> mechanism.<\/li>\n<li>In the first step, the aromatic ring, acting as a <strong>nucleophile<\/strong>, attacks an <strong>electrophile<\/strong> (E+).<\/li>\n<li>This\u00a0 is the <strong>slow<\/strong> (rate-determining) step since it disrupts aromaticity and results in a<strong> carbocation intermediate<\/strong>.<\/li>\n<li>In the second (fast) step a C-H bond is <strong>deprotonated<\/strong> to re-form a C-C pi bond, restoring aromaticity.<\/li>\n<li>The first step resembles attack of an alkene on H+, and the second step resembles the second step of the E1 reaction. The end result is\u00a0<strong>substitution<\/strong>. (Break C-H, form C-E).<\/li>\n<\/ul>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignnone wp-image-15859\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\" alt=\"electrophilic aromatic substitution summary electron donating substituents increase rate ewgs decrease rate\" width=\"600\" height=\"377\" \/><\/p>\n<p><strong>Table of Contents<\/strong><\/p>\n<ol>\n<li><a href=\"#one\">Electrophilic Aromatic Substitution Mechanism,\u00a0 Step 1: Attack of The Electrophile (E) By a Pi-bond Of The Aromatic Ring<\/a><\/li>\n<li><a href=\"#two\">Electrophilic Aromatic Substitution Mechanism, Step 2: Deprotonation Of The Tetrahedral Carbon Regenerates The Pi Bond<\/a><\/li>\n<li><a href=\"#three\">Putting Two Steps Together: The General Mechanism<\/a><\/li>\n<li><a href=\"#four\">The Reaction Energy Diagram of Electrophilic Aromatic Substitution<\/a><\/li>\n<li><a href=\"#five\">Beyond Benzene: Formation Of Ortho, Meta, and Para Disubstituted Benzenes<\/a><\/li>\n<li><a href=\"#six\">EAS On Monosubstituted Benzenes: The Distribution Of Ortho, Meta and Para Isomers Is NOT Random<\/a><\/li>\n<li><a href=\"#notes\">Notes<\/a><\/li>\n<li><a href=\"#quizzes\">Quiz Yourself!\u00a0<\/a><\/li>\n<li><a href=\"#references\">(Advanced) References and Further Reading<\/a><\/li>\n<\/ol>\n<hr \/>\n<h2><strong><a id=\"one\"><\/a>1. Electrophilic Aromatic Substitution Mechanism,\u00a0 Step 1: Attack of The Electrophile (E) By a Pi-bond Of The Aromatic Ring<\/strong><\/h2>\n<p>Last post in this series on reactions of aromatic groups we introduced <a href=\"https:\/\/www.masterorganicchemistry.com\/2017\/09\/26\/activating-and-deactivating-groups-in-electrophilic-aromatic-substitution\/\">activating and deactivating groups in Electrophilic Aromatic Substitution (EAS)<\/a>. We learned that electron-donating substituents on the aromatic ring <strong>increase<\/strong> the reaction rate and electron-withdrawing substituents <strong>decrease<\/strong> the rate. <span style=\"color: #993366;\"><em>[In the fine print, we also mentioned that evidence strongly suggests that the reaction proceeds through a carbocation intermediate, and that breakage of C-H is\u00a0<strong>not<\/strong> the slow step.]<\/em><\/span><\/p>\n<p>Having established these facts, we&#8217;re now ready to go into the general mechanism of this reaction.<\/p>\n<p>It&#8217;s a two-step process.<\/p>\n<p>The good news is that you&#8217;ve actually seen<strong> both<\/strong> of the steps before (in Org 1) but as part of different reactions!<\/p>\n<p>The first step of electrophilic aromatic substitution is attack of the electrophile (E+) by a pi bond of the aromatic ring.\u00a0<em>[<span style=\"color: #993366;\">Note: the identity of the electrophile E is specific to each reaction, and generation of the active electrophile is a mechanistic step in itself. We&#8217;ll cover the specific reactions next. This post just covers the general framework for electrophilic aromatic substitution<\/span>].\u00a0<\/em><\/p>\n<p><img decoding=\"async\" class=\"alignnone wp-image-15860\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/1-step-one-of-electrophilic-aromatic-substitution-is-attack-of-aromatic-ring-on-electrophile-giving-carbocation-intermediate.gif\" alt=\"step one of electrophilic aromatic substitution is attack of aromatic ring on electrophile giving carbocation intermediate\" width=\"600\" height=\"275\" \/><\/p>\n<p>Where have we seen this type of step before? In the chapter on alkenes, we saw a whole series of reactions of pi bonds with electrophiles that generate a carbocation. A common example is the reaction of alkenes with a strong acid such as H-Cl, leading to formation of a carbocation. The reaction above is the same step, only applied to an aromatic ring.<\/p>\n<p><img decoding=\"async\" class=\"alignnone wp-image-15861\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/2-first-step-of-electrophilic-aromatic-substitution-resembles-first-step-of-addition-of-alkenes-to-hcl-giving-carbocation.gif\" alt=\"first step of electrophilic aromatic substitution resembles first step of addition of alkenes to hcl giving carbocation\" width=\"600\" height=\"226\" \/><\/p>\n<p>You might recall that the second step of addition of HCl to alkenes is the attack of Cl on the carbocation, generating a new C-Cl bond. That&#8217;s not what happens in electrophilic aromatic substitution. [<a href=\"#noteone\">Note 1<\/a>]<\/p>\n<h2><strong><a id=\"two\"><\/a>2. Electrophilic Aromatic Substitution Mechanism, Step 2: Deprotonation Of The Tetrahedral Carbon Regenerates The Pi Bond<\/strong><\/h2>\n<p>The second step of electrophilic aromatic substitution is\u00a0<em>deprotonation.<\/em>\u00a0This breaks C\u2013H and forms C\u2013C (\u03c0),\u00a0restoring aromaticity. You may recall that this is strongly favored &#8211; the resonance energy of benzene is about 36 kcal\/mol. <span style=\"color: #993366;\"><em>[This is the type of phenomenon chemists like to call a &#8220;thermodynamic sink&#8221; &#8211; over time, the reaction will eventually flow to this final product, and stay there. ]<\/em><\/span><a href=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2017\/10\/3-EAS-step-2.png\"><br \/>\n<\/a><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15862\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/3-step-2-of-electrophilic-aromatic-substitution-is-deprotonation-of-carbon-adjacent-to-carbocation-restoring-aromaticity.gif\" alt=\"step 2 of electrophilic aromatic substitution is deprotonation of carbon adjacent to carbocation restoring aromaticity\" width=\"600\" height=\"302\" \/><a href=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2017\/11\/3-EAS-step-2-e1510156164331.png\"><br \/>\n<\/a>Have we seen this type of step before? Yes &#8211; it&#8217;s essentially the second step of the<a href=\"https:\/\/www.masterorganicchemistry.com\/2012\/09\/19\/the-e1-reaction\/\"> E1 reaction<\/a>, (after loss of a leaving group) where a carbon adjacent to a carbocation is deprotonated, forming a new C-C pi bond.<\/p>\n<h3><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15863\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/4-step-2-of-electrophilic-aromatic-substitution-resembles-step-2-of-e1-reaction.gif\" alt=\"step 2 of electrophilic aromatic substitution resembles step 2 of e1 reaction\" width=\"600\" height=\"221\" \/><\/h3>\n<p>Just as in the E1, a strong base is not required here. A halogen atom (such as Cl<sup>&#8211;<\/sup> ) will usually suffice, as will any number of other weak bases, such as H<sub>2<\/sub>O. The exact identity of the base depends on the reagents and solvent used in the reaction.<\/p>\n<h2><a id=\"three\"><\/a>3. Putting Two Steps Together: The General Mechanism<\/h2>\n<p>Let&#8217;s combine both steps to show the full mechanism. Again, we won&#8217;t go into the details of generating the electrophile E, as that&#8217;s specific to each reaction.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15864\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/5-full-mechanism-of-electrophilic-aromatic-substitution-step-1-attack-of-electrophile-step-2-deprotonation-giving-alkene.gif\" alt=\"full mechanism of electrophilic aromatic substitution step 1 attack of electrophile step 2 deprotonation giving alkene\" width=\"600\" height=\"303\" \/><\/p>\n<p>Note that attack could have occurred at any one of the six carbons of benzene and resulted in the same product.<\/p>\n<h2><strong><a id=\"four\"><\/a>4. The Reaction Energy Diagram of Electrophilic Aromatic Substitution<\/strong><\/h2>\n<p>What might the reaction energy diagram of electrophilic aromatic substitution look like?<\/p>\n<p>First, the overall appearance is determined by the number of transition states in the process.<\/p>\n<p>Recall that <a href=\"https:\/\/www.masterorganicchemistry.com\/2010\/11\/03\/whats-a-transition-state\/\">transition states<\/a> always have partial bonds and are at the <strong>&#8220;peaks&#8221;<\/strong> of a reaction energy diagram,\u00a0 and\u00a0<em>intermediates<\/em> such as carbocations are in the &#8220;valleys&#8221; between peaks.\u00a0 Intermediates can be observed and isolated <em>(at least in theory)<\/em>; in contrast, transition states have a lifetime of <a href=\"https:\/\/en.wikipedia.org\/wiki\/Femtosecond\">femtoseconds,<\/a> and although they may fleetingly be observed in <a href=\"https:\/\/en.wikipedia.org\/wiki\/Ahmed_Zewail\">certain cases<\/a>, they can never be isolated.<\/p>\n<p>Electrophilic aromatic substitution has two steps (attack of electrophile, and deprotonation) which each have their own transition state. There is also a carbocation intermediate. This means that we should have a &#8220;double-humped&#8221; reaction energy diagram.<\/p>\n<p>Second, the relative heights of the &#8220;peaks&#8221; should reflect the rate-limiting step.<\/p>\n<p>What&#8217;s the slow step? In other words, which of the two steps has the highest activation energy?<\/p>\n<p>One clue is to measure the effect that small modifications to the starting material have on the reaction rate.<\/p>\n<p>We showed in the last post that<strong> electron-donating substitutents increase the rate of reaction<\/strong> (&#8220;activating&#8221;) and <strong>electron-withdrawing substituents decrease the rate of reaction<\/strong> (&#8220;deactivating&#8221;). <em>[<span style=\"color: #993366;\">Conversely, <a style=\"color: #993366;\" href=\"https:\/\/en.wikipedia.org\/wiki\/Kinetic_isotope_effect\">substitution of hydrogen for deuterium<\/a> has very little effect on the reaction rate, which leads us to conclude that the second step is <strong>not<\/strong> rate-determining.<\/span> ]<\/em><\/p>\n<p>Since electron-donating and electron-withdrawing substitutents affect the nucleophilicity of the pi bond (through pi-donation and pi-acceptance) as well as the stability of the intermediate carbocation, <strong>the logical conclusion is that attack on the electrophile (step 1) is the rate-determining step.\u00a0<\/strong>We therefore should depict it with the higher &#8220;hump&#8221; in our reaction energy diagram, representing its higher activation energy.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15865\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/6-reaction-energy-diagram-of-electrophilic-aromatic-substitution-two-transition-states-and-carbocation-intermediate.gif\" alt=\"reaction energy diagram of electrophilic aromatic substitution two transition states and carbocation intermediate\" width=\"600\" height=\"471\" \/><\/p>\n<p>Note that this reaction energy diagram is not to scale and is more of a sketch than anything else. A truly accurate reaction energy diagram can be modelled if one had accurate energies of the transition states and intermediates, which is sometimes available through calculation.<\/p>\n<h2><strong><a id=\"five\"><\/a>5. Beyond Benzene: Formation Of Ortho, Meta, and Para Disubstituted Benzenes<\/strong><\/h2>\n<p>So that&#8217;s all there is to electrophilic aromatic substitution? Yes and no.<\/p>\n<p>Yes, this addresses electrophilic aromatic substitution for benzene.<\/p>\n<p>But, as you&#8217;ve no doubt experienced, small changes in structure can up the complexity a notch.<\/p>\n<p>Imagine we start not with benzene, but with a mono-substituted derivative, such as methylbenzene (toluene).<\/p>\n<p>What are the possible products of electrophilic aromatic substitution on a mono-substituted benzene derivative?<\/p>\n<p>Unlike with benzene, where only <strong>one<\/strong> EAS product is possible due to the fact that all six hydrogens are equivalent, electrophilic aromatic substitution on a mono-substituted derivative can yield<strong>\u00a0<em>three<\/em><\/strong> possible products: the 1,2- isomer (also called &#8220;<em>ortho<\/em>&#8220;), the 1,3-isomer (&#8220;<em>meta<\/em>&#8220;) and the 1,4-isomer (&#8220;<em>para<\/em>&#8220;).<\/p>\n<p>If we assume that the reaction obeys the laws of statistics, we might therefore expect that the product distribution should be 40%\u00a0<em>ortho<\/em>. 40%\u00a0<em>meta<\/em>, and\u00a020%\u00a0<em>para<\/em>.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15866\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/7-electrophilic-aromatic-substitution-on-monosubstituted-benzene-gives-ortho-meta-para-products.gif\" alt=\"electrophilic aromatic substitution on monosubstituted benzene gives ortho meta para products\" width=\"630\" height=\"391\" \/><\/p>\n<p>So is that what happens?<\/p>\n<p><strong>No!\u00a0<\/strong>Two important examples are illustrative.<\/p>\n<h2><strong><a id=\"six\"><\/a>6. EAS On Monosubstituted Benzenes: The Distribution Of Ortho, Meta and Para Isomers Is NOT Random!<\/strong><\/h2>\n<p>In the nitration of toluene, the product distribution is far from statistical. We get\u00a0<em>much<\/em> less meta (5%) than expected, and more <em>ortho <\/em>(57%)\u00a0and\u00a0<em>para <\/em>(37%) than expected.<\/p>\n<p>In this sense we can say that the methyl group tends to act as an\u00a0<em>ortho-\u00a0<\/em><em>para-\u00a0<\/em>director: it &#8220;directs&#8221; the electrophile to these positions at the expense of the\u00a0<em>meta\u00a0<\/em>position.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15867\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/8-nitration-of-toluene-gives-mostly-ortho-and-para-products-therefore-methyl-group-is-an-ortho-para-director.gif\" alt=\"nitration of toluene gives mostly ortho and para products therefore methyl group is an ortho para director\" width=\"600\" height=\"348\" \/><\/p>\n<p>Is this the case for all substituents? <strong>No.\u00a0<\/strong><\/p>\n<p>In the nitration of nitrobenzene, the opposite result is obtained. Much less\u00a0<em>ortho\u00a0<\/em>and\u00a0<em>para<\/em> is produced than expected, and the\u00a0<em>meta<\/em> product is major (93%).<\/p>\n<p>In this case the nitro group is said to be acting as a\u00a0<em>meta-<\/em> director.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15868\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/9-nitration-of-nitrobenzene-gives-meta-nitrobenzene-example-of-no2-being-a-meta-director.gif\" alt=\"nitration of nitrobenzene gives meta nitrobenzene example of no2 being a meta director\" width=\"630\" height=\"314\" \/><\/p>\n<p>Substituents on benzene tend to fall into one of two categories: <em>ortho<\/em>&#8211;<em>para<\/em> directors, or meta directors.<\/p>\n<p>If you&#8217;re sharp, you might have already made an intuitive leap: the\u00a0<em>ortho- para-\u00a0<\/em>directing\u00a0methyl group is an activating group, and the\u00a0<em>meta-\u00a0<\/em>directing nitro group is deactivating. So, therefore,\u00a0 are all activating groups\u00a0<em>ortho- para-\u00a0<\/em>directors and all deactivating groups\u00a0<em>meta-\u00a0<\/em>directors?<\/p>\n<p>It&#8217;s a good guess &#8211; and\u00a0<em>almost\u00a0<\/em>accurate! The fly in the bourbon is the halogens (F, Cl, Br, I) which are <strong>deactivating ortho-para directors.<\/strong><\/p>\n<p>Why? What leads some substituents to be ortho-para directors, and others to be meta-directors?<\/p>\n<p>That&#8217;s going to have to wait until the next post for a full discussion. But here&#8217;s a hint: it has to do with our old friend, &#8220;pi-donation&#8221;.<\/p>\n<p><strong>Thanks to Mattbew Knowe for valuable assistance with this post.\u00a0<\/strong><\/p>\n<hr \/>\n<h2><a id=\"notes\"><\/a>Notes<\/h2>\n<div class=\"related-articles\"><p><strong>Related Articles<\/strong><\/p><ul><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/04\/18\/electrophilic-aromatic-substitutions-1-halogenation\/\" class=\"\"><span>Electrophilic Aromatic Substitutions (1) \u2013 Halogenation of Benzene<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/04\/30\/electrophilic-aromatic-substitutions-2-nitration-and-sulfonation\/\" class=\"\"><span>Electrophilic Aromatic Substitutions (2) \u2013 Nitration and Sulfonation<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/11\/26\/sulfonyl-blocking-groups-aromatic-synthesis\/\" class=\"\"><span>Aromatic Synthesis (3) \u2013 Sulfonyl Blocking Groups<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/05\/17\/friedel-crafts-alkylation-acylation\/\" class=\"\"><span>EAS Reactions (3) \u2013 Friedel-Crafts Acylation and Friedel-Crafts Alkylation<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/05\/30\/intramolecular-friedel-crafts-reactions\/\" class=\"\"><span>Intramolecular Friedel-Crafts Reactions<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/organic-chemistry-practice-problems\/aromatic-reactions-and-synthesis-practice\/\" class=\"\"><span>Aromatic Reactions and Synthesis Practice (MOC Membership)<\/span><\/a><\/li><li><a href=\"https:\/\/www.masterorganicchemistry.com\/2018\/02\/02\/understanding-ortho-para-meta-directors\/\" class=\"\"><span>Understanding Ortho, Para, and Meta Directors<\/span><\/a><\/li><\/ul><\/div>\n<p><a id=\"noteone\"><\/a><strong>Note 1<\/strong> &#8211; Why can&#8217;t the counterion attack the aromatic ring carbocation? Does that happen?<\/p>\n<p><strong>Yes, but it&#8217;s a dead end.<\/strong><\/p>\n<p>Let&#8217;s say we form the carbocation, and it&#8217;s attacked by a weak nucleophile (which we&#8217;ll call X).<\/p>\n<p>This gives us the addition product.<\/p>\n<p>However, it&#8217;s rarely a very stable product. X is typically a weak nucleophile, and therefore a good leaving group. Furthermore, loss of the leaving group will result in a highly resonance-stabilized carbocation. (Think of the first step in the SN1 or E1 reaction).<\/p>\n<p>This would re-generate the carbocation, which could then undergo deprotonation to restore aromaticity. Once that aromatic ring is formed, it&#8217;s not going anywhere. : &#8211; )<\/p>\n<p>To make a long story short,\u00a0<strong>yes, addition could occur, but the addition product will eventually undergo E1 to form the aromatic product.\u00a0<\/strong><\/p>\n<p>(figure below)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-15869\" src=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/F1-isnt-it-possible-for-halide-to-add-to-carbocation-intermediate-yes-but-aromatic-molecule-is-thermodynamic-sink.gif\" alt=\"isnt it possible for halide to add to carbocation intermediate - yes but aromatic molecule is thermodynamic sink\" width=\"550\" height=\"635\" \/><\/p>\n<hr \/>\n<h2><a id=\"quizzes\"><\/a>Quiz Yourself!<\/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\/3090-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\/3091-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\/3092-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\/3093-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\/3094-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>The EAS mechanism covers a variety of reactions \u2013 Friedel-Crafts substitutions, halogenation, nitration, and many others.<\/p>\n<ol>\n<li><strong>A Quantum Mechanical Investigation of the Orientation of Substituents in Aromatic Molecules<br \/>\n<\/strong>G. W. Wheland<strong><br \/>\n<\/strong><em>Journal of the American Chemical Society<\/em> <strong>1942,<\/strong> <em>64<\/em> (4), 900-908<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ja01256a047\">10.1021\/ja01256a047<\/a><br \/>\nThis discusses the structure of the arenium ion that gets formed in EAS reactions, also known as the s-complex or Wheland intermediate, after the author here who first proposed it.<\/li>\n<li><strong>A Quantitative Treatment of Directive Effects in Aromatic Substitution<br \/>\n<\/strong>Leon M. Stock, Herbert C. Brown<strong><br \/>\n<\/strong><em> Phys. Org. Chem.<\/em><strong> 1963, <\/strong><em>1<\/em>, 35-154<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/www.sciencedirect.com\/bookseries\/advances-in-physical-organic-chemistry\/vol\/1\/suppl\/C\">10.1016\/S0065-3160(08)60277-4<\/a><br \/>\nThis is a very comprehensive review for its time, summarizing work on directing effects in EAS (e.g. determining which groups are <em>o\/p-<\/em>directing vs. <em>meta<\/em>-directing, and to what extent they direct\/deactivate).<\/li>\n<li><strong>Aromatic substitution. XXVIII. Mechanism of electrophilic aromatic substitutions<br \/>\n<\/strong>George A. Olah<strong><br \/>\n<\/strong><em>Acc. Chem. Res.,<\/em><strong> 1971, <\/strong><em>4<\/em> (7), 240-248<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ar50043a002\">10.1021\/ar50043a002<\/a><br \/>\nAn account by Prof. Olah on the work he had carried out studying the mechanism of various types of electrophilic aromatic substitution reactions \u2013 nitration, halogenation, as well as Friedel-Crafts acylation and alkylation.<\/li>\n<li><strong>Aromatic substitution. XXXVI. Aluminum trichloride and antimony pentafluoride catalyzed Friedel-Crafts alkylation of benzene and toluene with esters and haloesters<br \/>\n<\/strong>George A. Olah and Jun Nishimura<strong><br \/>\n<\/strong><em>Journal of the American Chemical Society<\/em><strong> 1974, <\/strong><em>96<\/em> (7), 2214-2220<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ja00814a035\">10.1021\/ja00814a035<\/a><br \/>\nIn this case, carboxylic esters are not studied (as those would lead to acylation rather than alkylation). This covers other types of esters in Friedel-Crafts alkylation: alkyl chlorosulfites, arenesulfinates, tosylates, chloro- and fluorosulfates, trifluoromethanesulfonates (triflates), pentafluorobenzenesulfonates, and trifluoroacetates.<\/li>\n<li><strong>Aromatic substitution. XXXVII. Stannic and aluminum chloride catalyzed Friedel-Crafts alkylation of naphthalene with alkyl halides. Differentiation of kinetically and thermodynamically controlled product compositions, and the isomerization of alkylnaphthalenes<br \/>\n<\/strong>George A. Olah and Judith A. Olah<strong><br \/>\n<\/strong><em>Journal of the American Chemical Society<\/em><strong> 1976, <\/strong><em>98<\/em> (7), 1839-1842<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/ja00423a032\">10.1021\/ja00423a032<\/a><br \/>\nThis is a similar paper by Prof. Olah and his wife, Judith Olah, on the mechanism of Friedel-Crafts alkylation, except using naphthalene instead of benzene. Naphthalene is different in that there are two sites for monosubstitution \u2013 the a and b positions.<\/li>\n<li><strong>Stable carbocations. CLXX. Ethylbenzenium ions and the heptaethylbenzenium ion<br \/>\n<\/strong>George A. Olah, Robert J. Spear, Guisseppe Messina, and Phillip W. Westerman<strong><br \/>\n<\/strong><em>Journal of the American Chemical Society<\/em><strong> 1975, <\/strong><em>97<\/em> (14), 4051-4055<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ja00847a031\">1021\/ja00847a031<\/a><br \/>\nThis paper discusses the characterization of benzenium ions, which are intermediates in EAS, and the characterization of the heptaethylbenzenium ion, which is a stable species because it lacks a proton and therefore eliminates with difficulty.<\/li>\n<li><strong>The Anomalous Reactivity of Fluorobenzene in Electrophilic Aromatic Substitution and Related Phenomena<br \/>\n<\/strong>Joel Rosenthal and David I. Schuster<strong><br \/>\n<\/strong><em>Journal of Chemical Education<\/em><strong> 2003, <\/strong><em>80<\/em> (6), 679<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/ed080p679\">10.1021\/ed080p679<\/a><br \/>\nA very interesting paper, suitable for curious undergrads, and discusses something that most practicing organic chemists will know empirically \u2013 fluorobenzene is almost as reactive as benzene in EAS or Friedel-Crafts reactions, which is counterintuitive when one considers electronic effects.<\/li>\n<li><strong>Electrophilic Aromatic Substitution: New Insights into an Old Class of Reactions<br \/>\n<\/strong>Boris Galabov, Didi Nalbantova, Paul von R. Schleyer, and Henry F. Schaefer, III<strong><br \/>\n<\/strong><em>Accounts of Chemical Research<\/em> <strong>2016,<\/strong> <em>49<\/em> (6), 1191-1199<strong><br \/>\nDOI: <\/strong><a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/acs.accounts.6b00120\">10.1021\/acs.accounts.6b00120<\/a><br \/>\nThe late Prof. P. v. R. Schleyer was a giant in Physical Organic chemistry, and this paper, published posthumously, covers work done towards the end of his life in re-determining the mechanism of EAS.<\/li>\n<li><strong>Unified Mechanistic Concept of Electrophilic Aromatic Nitration:\u2009 Convergence of Computational Results and Experimental Data<\/strong><br \/>\nPierre M. Esteves, Jos\u00e9 Walkimar de M. Carneiro, Sheila P. Cardoso, Andr\u00e9 H. Barbosa, Kenneth K. Laali, Golam Rasul, G. K. Surya Prakash, and George A. Olah<br \/>\n<em>Journal of the American Chemical Society<\/em> <strong>2003,<\/strong> <em>125<\/em> (16), 4836-4849<br \/>\n<strong>DOI:<\/strong> <a href=\"https:\/\/pubs.acs.org\/doi\/10.1021\/ja021307w\">10.1021\/ja021307w<\/a><br \/>\nThis is the grand-daddy paper on nitration, summarizing a lifetime\u2019s worth of work on the subject.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>Electrophilic Aromatic Substitution: The Mechanism Electrophilic aromatic substitution (EAS) reactions proceed through a two-step mechanism. In the first step, the aromatic ring, acting as a <\/p>\n","protected":false},"author":1,"featured_media":15859,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1297],"tags":[294,320,472,1284,319,232,1285,305,1286],"post_folder":[],"class_list":["post-11147","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-aromatic-reactions","tag-addition","tag-aromaticity","tag-e1","tag-eas","tag-electrophilic-aromatic-substitution","tag-mechanism","tag-ortho-para-meta","tag-pi-donation","tag-reaction-energy-diagram"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry<\/title>\n<meta name=\"description\" content=\"Let&#039;s review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...\" \/>\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\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry\" \/>\n<meta property=\"og:description\" content=\"Let&#039;s review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/\" \/>\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=\"2017-11-09T19:32:53+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-02-28T18:10:09+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\" \/>\n\t<meta property=\"og:image:width\" content=\"870\" \/>\n\t<meta property=\"og:image:height\" content=\"546\" \/>\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=\"13 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/\"},\"author\":{\"name\":\"James Ashenhurst\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#\\\/schema\\\/person\\\/78d83ec7d02b4b7365bade2cedaef80c\"},\"headline\":\"Electrophilic Aromatic Substitution &#8211; The Mechanism\",\"datePublished\":\"2017-11-09T19:32:53+00:00\",\"dateModified\":\"2025-02-28T18:10:09+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/\"},\"wordCount\":2338,\"commentCount\":20,\"publisher\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#organization\"},\"image\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/12\\\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\",\"keywords\":[\"addition\",\"aromaticity\",\"e1\",\"EAS\",\"electrophilic aromatic substitution\",\"mechanism\",\"ortho para meta\",\"pi donation\",\"reaction energy diagram\"],\"articleSection\":[\"Reactions of Aromatic Molecules\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/\",\"name\":\"Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/12\\\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\",\"datePublished\":\"2017-11-09T19:32:53+00:00\",\"dateModified\":\"2025-02-28T18:10:09+00:00\",\"description\":\"Let's review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/12\\\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\",\"contentUrl\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/wp-content\\\/uploads\\\/2019\\\/12\\\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif\",\"width\":870,\"height\":546,\"caption\":\"electrophilic aromatic substitution summary electron donating substituents increase rate ewgs decrease rate\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/2017\\\/11\\\/09\\\/electrophilic-aromatic-substitution-the-mechanism\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.masterorganicchemistry.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Electrophilic Aromatic Substitution &#8211; The Mechanism\"}]},{\"@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":"Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry","description":"Let's review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...","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\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/","og_locale":"en_US","og_type":"article","og_title":"Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry","og_description":"Let's review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...","og_url":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/","og_site_name":"Master Organic Chemistry","article_publisher":"https:\/\/www.facebook.com\/Master-Organic-Chemistry-242610599108055\/","article_published_time":"2017-11-09T19:32:53+00:00","article_modified_time":"2025-02-28T18:10:09+00:00","og_image":[{"width":870,"height":546,"url":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif","type":"image\/gif"}],"author":"James Ashenhurst","twitter_card":"summary_large_image","twitter_misc":{"Written by":"James Ashenhurst","Est. reading time":"13 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#article","isPartOf":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/"},"author":{"name":"James Ashenhurst","@id":"https:\/\/www.masterorganicchemistry.com\/#\/schema\/person\/78d83ec7d02b4b7365bade2cedaef80c"},"headline":"Electrophilic Aromatic Substitution &#8211; The Mechanism","datePublished":"2017-11-09T19:32:53+00:00","dateModified":"2025-02-28T18:10:09+00:00","mainEntityOfPage":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/"},"wordCount":2338,"commentCount":20,"publisher":{"@id":"https:\/\/www.masterorganicchemistry.com\/#organization"},"image":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#primaryimage"},"thumbnailUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif","keywords":["addition","aromaticity","e1","EAS","electrophilic aromatic substitution","mechanism","ortho para meta","pi donation","reaction energy diagram"],"articleSection":["Reactions of Aromatic Molecules"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/","url":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/","name":"Electrophilic Aromatic Substitution Mechanism &#8211; Master Organic Chemistry","isPartOf":{"@id":"https:\/\/www.masterorganicchemistry.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#primaryimage"},"image":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#primaryimage"},"thumbnailUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif","datePublished":"2017-11-09T19:32:53+00:00","dateModified":"2025-02-28T18:10:09+00:00","description":"Let's review what we know so far and propose a mechanism for electrophilic aromatic substution. First, the aromatic ring attacks an electrophile. Next...","breadcrumb":{"@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#primaryimage","url":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif","contentUrl":"https:\/\/www.masterorganicchemistry.com\/wp-content\/uploads\/2019\/12\/0-electrophilic-aromatic-substitution-summary-electron-donating-substituents-increase-rate-ewgs-decrease-rate.gif","width":870,"height":546,"caption":"electrophilic aromatic substitution summary electron donating substituents increase rate ewgs decrease rate"},{"@type":"BreadcrumbList","@id":"https:\/\/www.masterorganicchemistry.com\/2017\/11\/09\/electrophilic-aromatic-substitution-the-mechanism\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.masterorganicchemistry.com\/"},{"@type":"ListItem","position":2,"name":"Electrophilic Aromatic Substitution &#8211; The Mechanism"}]},{"@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\/11147","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=11147"}],"version-history":[{"count":0,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/posts\/11147\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/media\/15859"}],"wp:attachment":[{"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/media?parent=11147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/categories?post=11147"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/tags?post=11147"},{"taxonomy":"post_folder","embeddable":true,"href":"https:\/\/www.masterorganicchemistry.com\/wp-json\/wp\/v2\/post_folder?post=11147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}