Comments on: Synthesis (2) – Reactions of Alkanes https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/ Thu, 14 May 2026 17:32:49 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: James Ashenhurst https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-794263 Thu, 14 May 2026 17:32:49 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-794263 In reply to Nithin K.

That is not a reaction that will be covered on this site.

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By: Nithin K https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-794164 Wed, 13 May 2026 07:25:49 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-794164 Pyrolysis and isomerisation by AlCl3 should also be considered as a reaction of alkanes right?

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By: James Ashenhurst https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-716714 Wed, 20 Nov 2024 15:18:52 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-716714 In reply to Susie Elmajian.

I’m going to be annoying and answer your first question with a question.

1) What is the IUPAC name of the chlorinated cyclohexane I drew?

2) What would be the IUPAC name of the product where the chlorine is attached to the top?

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[Writing articles where people have to scroll down, I try to minimize the vertical space each image occupies. So that gives you some ideas of my motivation for writing it that particular way]

With the reaction with Br, the starting material is not the same as in the first example. It is cyclohexane with a methyl group attached. The Br is *selective* for the carbon which is attached to the fewest carbons (i.e. the carbon attached to the methyl group).

Thanks for your comment – I had no idea this might trip people up.

Bottom line – in the Cl example, it would still be correct for Cl to attach to any carbon around the ring because they all give 1-chlorocyclohexane. Bromine would also give only 1-bromocyclohexane

With methylcyclohexane, the correct answer is to show Br attaching preferentially to the carbon bearing the methyl group to give 1-bromo-1-methylcyclohexane since Br is highly selective for tertiary C-H. If we drew Br on any other carbon it would be wrong.

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By: Susie Elmajian https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-716649 Wed, 20 Nov 2024 05:31:42 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-716649 Why is the Chlorine in the cyclohexane on that particular part of the ring? Is it because Cl specifically has to be there? What about if it was Br? It would be all the way on the top of the ring if it was Br2, can you please explain in easier terms why Cl is attached there on the ring and not all the way on the top?

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By: James Ashenhurst https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-587930 Wed, 11 Nov 2020 18:00:52 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-587930 In reply to AF.

Absolutely! Doesn’t get covered very often, but the reaction of C-H bonds with molecular oxygen to give C-OOH primarily occurs with tertiary C-H bonds, C-H bonds adjacent to oxygen (e.g. ethers) and benzylic and allylic C-H bonds.

This is why saturated fats (e.g. margarine) are much less likely to spoil when left out in air than unsaturated fats (e.g. butter)…

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By: AF https://www.masterorganicchemistry.com/2013/12/19/synthesis-reactions-of-alkanes/#comment-587882 Wed, 11 Nov 2020 01:19:11 +0000 https://www.masterorganicchemistry.com/?p=7850#comment-587882 Hi,

Could autooxidation also be considered a reaction of alkanes? I recently came across a problem in my textbook in which methylcyclohexane was converted to methylcyclohexene via auto-oxidation followed by reduction and treatment with an acid.

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