Chapter 23.9, Problem 15P

Interpretation Introduction

Interpretation:

Given that Dieckmann cyclization of 3-methylheptanedioate gives a mixture of two β keto esters as products. Their structures are to be given and the formation of a mixture of two β keto esters as product is to be explained.

Concept introduction:

Diesters can undergo intramolecular cyclization reactions to yield cyclic esters. This reaction is called Dieckmann cyclization. In this reaction 1,6-diesters give a five membered cyclic β-keto esters while 1,7-diesters give a six membered cyclic β-keto esters. One of the ester groups is converted into an enolate anion, which then carries out a nucleophilic acyl substitution on the second ester group at the other end of the molecule.

To give:

The structures of two β keto esters obtained as products in the Dieckmann cyclization of 3-methylheptanedioate are to be given.

To explain:

Why a mixture of two β keto esters is formed in this reaction.