Saponification Practice Problems

The labeled intermediate is formed during the base-catalyzed hydrolysis of the ester. Propose a suitable mechanism for the following transformations:

A Russian chemist investigated the hydrolysis of an ester by a hydroxide ion and discovered that the alkyl C—O bond remains intact while the acyl C—O bond breaks. 

a. Draw the product of the hydrolysis of the following ester. 

b. What would be the product if the alkyl C—O bond had broken?

Predict the product(s) for the following reaction and propose a mechanism.

Optically pure (R)-pentan-2-yl propionate was labeled with oxygen-18 at one of the oxygen atoms as shown in the structure below.

Propose a mechanism for the base-catalyzed hydrolysis of this compound showing the stereochemistry of the product. Also, show which of the product will have the oxygen-18 labeled.

Draw a mechanism for the hydrolysis of 5-hydroxypentanoic acid lactone in the presence of a base.

Consider the following reactions. The first hydrolysis reaction of the ester is called acid-catalyzed, while the second hydrolysis reaction of the ester is referred to as base-promoted rather than base-catalyzed. Explain why.

Two hydrolysis reactions are shown below. Soap manufacturers use the first reaction rather than the second one. Provide two reasons why basic hydrolysis is usually preferred.

What product(s) will be formed in the saponification reaction of the ester given below?

What product(s) are expected from the saponification reaction of the ester shown below?

Predict the product formed when the given ester is subjected to saponification.

What product(s) will be obtained in the saponification reaction of the ester given below?

Ethyl p-nitrobenzoate is observed to saponify more rapidly than ethyl benzoate. Analyze the saponification mechanism and explain the reason for this increased reaction rate.

Would ethyl p-methoxybenzoate be expected to saponify more slowly or more quickly than ethyl benzoate?

Complete the given reactions.

Propose a plausible mechanism for the base catalyzed hydrolysis of the compound shown below.

Propose a plausible mechanism for the acid-catalyzed hydrolysis of the compound shown below.

Suggest a suitable mechanism to show the base-catalyzed hydrolysis of 2-phenylacetonitrile into 2-phenylacetate and ammonia.