Comments on: Claisen Condensation and Dieckmann Condensation

By: James Ashenhurst

James Ashenhurst — Fri, 07 Oct 2022 09:17:36 +0000

Hi, if the ester is treated with hydroxide ion HO(-) that will convert it into a carboxylic acid (and then a carboxylate salt) which is a saponification.

If the ester is treated with an alkoxide base RO(-) then one thing that could happen is not saponification, but *transesterificaation* which is a nucleophilic acyl substitution reaction. E.g. CH3COOCH3 plus NaOCH2CH3 could give CH3COOCH2CH3 plus NaOCH3.

To avoid transesterification in the Claisen we usually make the added base the same as whatever is attached to the ester.

By: Luce Muzi

Luce Muzi — Fri, 07 Oct 2022 06:13:42 +0000

Hi! Quick question, if the ester is treated with a strong base wouldn’t the the reaction be a saponification instead?

By: James Ashenhurst

James Ashenhurst — Wed, 20 Jul 2022 20:13:12 +0000

In reply to Aarav. It can, but it's reversible. Like driving down a dead-end street, eventually it will reverse course and go somewhere else.

By: Aarav

Aarav — Mon, 27 Dec 2021 17:31:48 +0000

I don’t get it- why doesn’t RO- just attack carbon in c=o for nucleophilic addition reaction in the first step?

By: James Ashenhurst

James Ashenhurst — Fri, 29 Jan 2021 04:37:32 +0000

In reply to Yami. No, the pdf guides are one-time downloads, whereas the monthly subscription is for the reaction guide and the quizzes, which are probably too big to download.

By: Yami

Yami — Tue, 19 Jan 2021 13:26:42 +0000

Will I have access to pdf guides if i pay for monthly course?