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25. Condensation Chemistry

Claisen Condensation

25. Condensation Chemistry

Claisen Condensation

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Claisen Condensation

Claisen Condensation

Johnny Betancourt

Practice this topic

Multiple Choice

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

Multiple Choice

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

Multiple Choice

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

Multiple Choice

Predict the major, organic product for the following reaction.

Multiple Choice

Predict the major, organic product for the following reaction sequence.

Textbook Question

Which of the following esters cannot undergo a Claisen condensation? A.

Textbook Question

Indicate how each of the following compounds can be synthesized from the given starting material and any other necessary reagents: b.

Textbook Question

Draw the products of the following reactions: a. diethyl heptanedioate: (1) sodium ethoxide; (2) HCl

Textbook Question

Draw the products of the following reactions: b.

Textbook Question

Draw the products of the following reactions: a.

Textbook Question

Draw the products of the following reactions: a.

Textbook Question

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?

Textbook Question

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)

Textbook Question

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

Textbook Question

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

Textbook Question

Predict the products of self-condensation of the following esters. (d)

Textbook Question

Predict the products of self-condensation of the following esters. (c)

Textbook Question

Predict the products of the following Claisen condensations. (e) <

Textbook Question

Predict the products of the following Claisen condensations. (d) <

Textbook Question

Predict the major products of the following crossed Claisen condensations. (c) <

Textbook Question

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

Textbook Question

Predict the major products of the following crossed Claisen condensations. (a) < of reaction>

Textbook Question

Predict the major products of the following crossed Claisen condensations. (b) < of reaction>

Textbook Question

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

Textbook Question

Propose mechanisms for the following reactions. (b) < of reaction>

Textbook Question

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. (a) (b)

Textbook Question

Propose a mechanism for the self-condensation of methyl 3-phenylpropionate promoted by sodium methoxide.

Textbook Question

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. (a) (b) (c) (d)

Textbook Question

Predict the products of the following Claisen condensations.

(c) <IMAGE of reaction>

Textbook Question

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

Textbook Question

Esters with only one α hydrogen generally give poor yields in the Claisen condensation. Propose a mechanism for the Claisen condensation of ethyl isobutyrate, and explain why a poor yield is obtained.

Textbook Question

Predict the products of self-condensation of the following esters.

(a) methyl propanoate + NaOCH3

(b) ethyl phenylacetate + NaOCH2CH3

Textbook Question

Predict the products from crossed Claisen condensation of the following pairs of esters. Indicate which combinations are poor choices for crossed Claisen condensations.

(a) <IMAGE of reaction>

(b) <IMAGE of reaction>

Textbook Question

Predict the products from crossed Claisen condensation of the following pairs of esters. Indicate which combinations are poor choices for crossed Claisen condensations.

(c) <IMAGE of reaction>

(d) <IMAGE of reaction>

Textbook Question

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

(d) <IMAGE>

Textbook Question

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

Textbook Question

Draw the products of the following reactions:

d. diethyl 1,2-benzenedicarboxylate + sodium ethoxide: (1) slow addition of ethyl acetate; (2) HCl

Textbook Question

Show how crossed Claisen condensations could be used

to prepare the following esters.

(a) <IMAGE>

Textbook Question

Show how crossed Claisen condensations could be used

to prepare the following esters.

(b) <IMAGE>

Textbook Question

Show how Claisen condensations could be used to make

the following compounds.

(a) <IMAGE>

Textbook Question

Show how Claisen condensations could be used to make

the following compounds.

(b) <IMAGE>

Textbook Question

Show how Claisen condensations could be used to make

the following compounds.

(c) <IMAGE>

Textbook Question

Show how Claisen condensations could be used to make

the following compounds.

(d) <IMAGE>

Textbook Question

Predict the products of the following Claisen condensations.

(a) <IMAGE of reaction>

(b) <IMAGE of reaction>

Textbook Question

There are other condensation reactions similar to the aldol and Claisen condensations: a. The Perkin condensation is the condensation of an aromatic aldehyde and acetic anhydride. Draw the product obtained from the following Perkin condensation:

Textbook Question

d. What product is obtained when the product of a Knoevenagel condensation is heated in an aqueous acidic solution?

Textbook Question

There are other condensation reactions similar to the aldol and Claisen condensations: c. The Knoevenagel condensation is the condensation of an aldehyde or a ketone that has no a-hydrogens and a compound such as diethyl malonate that has an a-carbon flanked by two electron-withdrawing groups. Draw the product obtained from the following Knoevenagel condensation:

Textbook Question

The Knoevenagel condensation is a special case of the aldol condensation in which an active methylene compound reacts with an aldehyde or ketone, in the presence of a secondary amine as a basic catalyst, to produce a new C=C. Show the starting materials that made each of these by a Knoevenagel condensation. (a)

Textbook Question

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

Textbook Question

Propose mechanisms for the reactions shown in

Problems 22-63 parts (b).

Textbook Question

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

(f) <IMAGE>

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