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.

Question

The following substances can be prepared by a nucleophilic addition reaction between an aldehyde or ketoneand a nucleophile. Identify the reactants from which they were prepared. If the substance is an acetal, identifythe carbonyl compound and the alcohol; if it is an imine or enamine, identify the carbonyl compound and theamine. You do not have to consider stereochemistry. In cases where there is more than one answer, just giveone. Use Grignard reagents when an organometallic reagent is required. Draw the Grignard reagent as acovalent magnesium bromide.

Answer 1

Question

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.

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