Module 1: Formation of Aliphatic Carbon-Carbon Bonds: Base Catalyzed Reactions

Lecture 2 : Base Catalyzed Reactions - II

1.2.2 Reactions with Esters and Analogues

1.2.2.1 The Claisen Condensation

The condensation of between esters is known as the Claisen condensation. It is important to note that an equivalent amount of base must be employed for this reaction (Scheme 1).

Mechanism

Scheme 1

Examples:

1.2.2.2 Dieckmann Condensation

Condensation of the diesters of having C6 and C7 can be accomplished to afford five and six membered cyclic β -ketoesters (Scheme 2). The diesters of short-chain do not show cyclization, while diesters with C8 and C9 provide the cyclized products in fewer yields .

Mechanism

Scheme 2