Comments on: Understanding Ortho, Para, and Meta Directors https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/ Tue, 13 Aug 2024 21:20:08 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: James Ashenhurst https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-692120 Fri, 26 Apr 2024 19:58:15 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-692120 In reply to Kevin Park.

Hi, I would highly recommend Ian Fleming’s “Frontier Orbitals and Organic Chemical Reactions” for a discussion of MO theory. Mostly covers pericyclic reactions, but it also does a frontier orbital treatment of electrophilic aromatic substitution.
https://archive.org/details/frontierorbitals0000flem

]]> By: Kevin Park https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-692083 Fri, 26 Apr 2024 14:14:20 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-692083 Thank you for great explanations! In this article, the reason why some substituents “direct” the electrophile to certain position is explained by resonance. However, since resonance is an imaginary concept that doesn’t actually take place in actual interaction of molecules, I have been trying to explain every resonance-induced stability with MO theory.
Well… it just didn’t work this time. I tried to explain the stability with idea based on pi system that the longer the conjugation, the more stable it is, and it could explain ortho and meta position (ortho has 6 atoms in pi system, where meta has two cases of 5 atoms in pi system) but it couldn’t explain the case of para position (one case of 4 atoms, one case of 5 atoms). And I wasn’t even sure that if using the pi system was the right approach(also having many different ways of conjugation that has different number of atoms in the system just felt so wrong).
So I went on to molecular calculation using MolCalc, and got the result that matches our expectations, but I still couldn’t explain it with MO theory.
Even if it is just what Schrödinger equation and Hückel method says, there still has to be the reason for that… and I just can’t find it but I’m dying to find it. Could you help?

]]> By: James Ashenhurst https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-635598 Thu, 18 Aug 2022 16:04:13 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-635598 In reply to SHRUTI SAURABH BANDYOPADHYAY.

Yes. Same effect. Lone pair on nitrogen can stabilize an adjacent carbocation.

]]> By: SHRUTI SAURABH BANDYOPADHYAY https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-604016 Sat, 31 Jul 2021 05:18:06 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-604016 Is (-NHCOPh) an Ortho/Para-directing group like (-NHCOCH3) ?
Will be obliged if you can give some explanation.

]]> By: James Ashenhurst https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-603236 Wed, 07 Jul 2021 15:14:13 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-603236 In reply to fazi.

A carbanion would have a lone pair.

]]> By: fazi https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-603226 Wed, 07 Jul 2021 09:17:10 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-603226 thank you for your nice explanation. but I have a question. why you said ‘most’ alkyl groups not all of them lack a lone pair?

]]> By: Nima https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-588653 Wed, 25 Nov 2020 17:04:53 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-588653 *xylen :)

]]> By: Nima https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-588652 Wed, 25 Nov 2020 17:02:33 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-588652 thanks for the article
why ortho-zailen and para-zailen tend to change into meta-zailen in 80 degrees Celsius in presence of HCL and AlCl3
but in 0 degree Celsius it doesn’t happen
how it happens?
depends on HCL or something else?

]]> By: Mujahid khan https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-581565 Thu, 25 Jun 2020 15:58:56 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-581565 Sir it is very beautiful explanation i understood complete concept of ortho , meta and para . Suprb explanation. Thankyou very much sir for .

]]> By: James Ashenhurst https://www.masterorganicchemistry.com/2018/02/02/understanding-ortho-para-meta-directors/#comment-568143 Fri, 18 Oct 2019 19:10:48 +0000 https://www.masterorganicchemistry.com/?p=11291#comment-568143 In reply to Mitchell.

Yes, you are correct. I will put this in the corrections queue.

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