Study Notes On DIECKMANN REACTION(Chemical Science) - Download PDF!

By Astha Singh|Updated : February 3rd, 2023

Are you an Aspirant of CSIR-NET and looking for some short and reliable notes for Chemical Sciences to strong your base for preparations? We have got you covered!

Candidates preparing for their CSIR NET exam can really make their preparation journey easier with the help of some reliable study notes that cover the topics in the most simple way. We at BYJU'S Exam Prep have come up with the idea of providing short notes On DIECKMANN REACTION which comes under the Organic Chemistry section of the Chemical Science syllabus. 

The short notes on DIECKMANN REACTION are developed by our experienced subject-matter experts to provide you with the most standard and authentic set of study materials to be focused upon. The students need the best resources for their preparation to clear the CSIR NET examination, Here are the most reliable study notes to make the topics easier for you and also help you to save your time for the preparations for the upcoming CSIR-NET 2023 exam.

DIECKMANN REACTION

(An Intramolecular Claisen Reaction)

It is an intramolecular condensation of the diester. In this reaction, the diester undergoes intramolecular condensation in presence of a base to yield β-ketoesters.

It is similar to intermolecular reaction, Claisen condensation. So, it is usually considered that the intramolecular Claisen condensation in dibasic acid esters is known as the Dieckmann reaction.

The Base catalyzed intramolecular cyclization of the dicarboxylic acid ester to yield β-keto-ester is a Dieckmann condensation reaction whose general reaction is as follows-

This reaction usually occurs when a 5 or 6-membered ring could be formed.

General Reaction-

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Note:

The reaction best proceeds with dibasic acid esters having 6, 7 or 8 carbon atoms which give stable rings with s, 6, or 7 carbons.  Yields for rings of 9 to 12 carbons are very low. High-dilution technique is used for the formation of large-size rings.

Reaction Mechanism-

A strong base removes the alpha proton resulting in an enolate. The enolate then attacks the carbonyl carbon of another ester molecule, resulting in a cyclic β-ketoester and regenerating the conjugate base. The base then deprotonates the cyclic compounds, and an acid workup is required to produce the final cyclic β-ketoester.

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This can also be understood as-

Dieckmann Condensation Mechanism-

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Note:

Due to the steric stability of five- and six-membered rings, these structures will preferentially be formed. 1,6 diesters will form five-membered cyclic β-keto esters, while 1,7 diesters will form six-membered β-keto esters.

Examples-

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Application of Dieckmann Condensation-

Dieckmann condensation is used in the preparation of cyclic indole. There has been a report on preparing five-membered pyrroles through this condensation method.

The reaction affords a useful route for the synthesis of cyclopentanone and cyclohexanone derivatives. Some examples are given for illustration.

1. The reaction has been used to build up to five- or six-membered rings in the synthesis of various natural products. The general process is given below.

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