Comments on: Deciding SN1/SN2/E1/E2 (1) – The Substrate

By: James Ashenhurst

James Ashenhurst — Wed, 05 Feb 2025 23:19:39 +0000

In reply to Aryavk18. Good question. I'm going to fix this quiz and put a CH3 on C-2 so this is unambiguous.

By: Aryavk18

Aryavk18 — Wed, 05 Feb 2025 13:41:47 +0000

hello sir,
in the question associated with MOC quiz-id 2502, will not the carbocation rearrange once more via 1,2-hydride shift to the position marked “1”, because in doing so it will obtain a larger number of alpha-hydrogen (7 vs 3 as compared to position marked “2”), leading to a greater extent of no-bond resonance?

By: James Ashenhurst

James Ashenhurst — Wed, 08 Jan 2025 14:24:33 +0000

In reply to kausik kolisetti. Really!?? I'd love to see it. Sodium ethoxide should be doing an elimination in that case, never a substitution.

By: kausik kolisetti

kausik kolisetti — Wed, 08 Jan 2025 09:34:24 +0000

Hello there I just wanted to know whether sodium ethoxide is a good base or a good nucleophile since there was a question in my exam where a tertiary halide was treated with sodium ethoxide in the presence of heat and we obtained a substitution product rather than elimination I always wondered sodium ethoxide was a good base

By: James Ashenhurst

James Ashenhurst — Tue, 03 Nov 2020 03:23:20 +0000

In reply to Hina Mumtaz.

Here would be the thought process:
1) Secondary carbon. Can’t rule anything out at this stage.
2) Identity of nucleophile/base: Br(-). Good nucleophile (negatively charged), weak base. Rule out E2 because E2 needs a strong base. Rule out SN1/E1 because they operate with weak (generally neutral) bases. That leaves SN2.
3) So draw product of SN2 with inversion of configuration.

By: Hina Mumtaz

Hina Mumtaz — Mon, 02 Nov 2020 15:42:58 +0000

ok so i have a question about what if in differentiating either an SN1 or an SN2 reaction lets say the substrate is a 6 carbon single chain on the 2nd carbon with a wedge of H and ladder on that same carbon with a Cl and a attacking nucleophile of Br-. how can you tell that this is an SN2?

For an Sn1 imagine a 5 carbon chain with carbon 2 has wedge of Br and ladder of H with nucleophile of Cl- how can you tell if its a SN1 reaction. like that what I’m having problem with. please let me know asap i have my exam on Thursday!

By: James Ashenhurst

James Ashenhurst — Sat, 30 May 2020 02:09:49 +0000

In reply to moreen. You might want to look into the subject of "double inversion" :-) especially in basic conditions.

By: moreen

moreen — Thu, 28 May 2020 18:07:09 +0000

hi, i was just wondering if a compound like (R) 2-bromopropan-1-ol was to undergo a substitution reaction with NaCN, and it resulted in the (R) configuration of the product with the bromine being substituted by the cyanide, which reaction mechanism does it do it by? SN1 or SN2?
can the compound undergo frontside attack by any mechanism because it is a secondary compound?

By: James Ashenhurst

James Ashenhurst — Mon, 13 May 2019 16:05:36 +0000

In reply to Prakash. Primary alkyl halide. Almost certainly an SN2 reaction.

By: Prakash

Prakash — Wed, 08 May 2019 11:56:47 +0000

Sir what product should I expect on treating ethylbromide with t butoxide. By the way great job on creating such a fabulous blog