25. Condensation Chemistry

Predict the products of the following Claisen condensations.

(e)

Show how crossed Claisen condensations could be used to prepare the following esters.

(b)

Predict the products of the following Claisen condensations.

(d)

There are other condensation reactions similar to the aldol and Claisen condensations:

b. What compound is formed if water is added to the product of a Perkin condensation?

Some (but not all) of the following keto esters can be formed by Dieckmann condensations. Determine which ones are possible, and draw the starting diesters.

(c)

(d)

Ethoxide is used as the base in the condensation of ethyl acetate to avoid some unwanted side reactions. Show what side reactions would occur if the following bases were used.

(a) sodium methoxide

(b) sodium hydroxide

Give the structure of the ester precursor for the following Claisen condensation product.

Draw the structure of the Claisen condensation product for each of the following compounds.

Show how you would use an aldol, Claisen, or another type of condensation to make each compound.

(d)

Show what esters would undergo Claisen condensation to give the following β-keto esters.

(b)

Show how Claisen condensations could be used to make the following compounds.

(b)

Draw the products of the following reactions:

a.

Write the mechanism for the reaction of a 1,7-diester with an alkoxide ion to form a cyclic b-keto ester.

Which of the following esters cannot undergo a Claisen condensation?