Chapter 22.SE, Problem 23MP

Interpretation Introduction

a)

Interpretation:

Whether the ketone obtained by the decarboxylation of the optically active β- keto acid will be optically active or not is to be stated. A mechanism to explain the formation of the ketone is to be proposed.

Concept introduction:

The decarboxylation of a β- keto acid takes place through the formation of a planar enol intermediate which then tautomerizes to the keto form. If the β- keto acid is optically active and if the chiral centre is involved in the reaction, the ketone product will be racemic and optically inactive. If the chiral centre is not involved in the reaction then the optical activity is retained in the ketone product.

To state:

Whether the ketone obtained by the decarboxylation of the optically active β- keto acid will be optically active or not.

To propose:

A mechanism to explain the formation of the ketone.

Interpretation Introduction

b)

Interpretation:

Whether the ketone obtained by the decarboxylation of the optically active β- keto acid will be optically active or not is to be stated. A mechanism to explain the formation of the ketone is to be proposed.

Concept introduction:

The decarboxylation of a β- keto acid takes place through the formation of a planar enol intermediate which then tautomerizes to the keto form. If the β- keto acid is optically active and if the chiral centre is involved in the reaction, the ketone product will be racemic and optically inactive. If the chiral centre is not involved in the reaction then the optical activity is retained in the ketone product.

To state:

Whether the ketone obtained by the decarboxylation of the optically active β- keto acid will be optically active or not.

To propose:

A mechanism to explain the formation of the ketone.