Organic Chemistry : Help with Ether and Ester Reactions

Study concepts, example questions & explanations for Organic Chemistry

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Example Questions

Example Question #1 : Help With Ether And Ester Reactions

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Predict the major product of the following reaction (the reaction is allowed to run to completion and the final step is an acid workup).

Possible Answers:

I

IV

II

III

None of these

Correct answer:

III

Explanation:

Alkyl lithium (organolithium) reagents are powerful reducing agents and react much in the same manner as Grignard reagents through the formation of a carbanion. In the first step of the reaction, the carbanion attacks at the carbonyl, creating a charged intermediate, which is neutralized by reformation of the carbonyl and the release of ethoxide (the ester chain is the leaving group). However, the alkyl lithium reagent continues the reaction by attacking at the carbonyl once again. This time, there is no suitable leaving group (every group bound is a carbon chain) and the intermediate remains until a proton transfer is facilitated to neutralize the oxygen's charge.

Example Question #42 : Reactions By Reactant

When butanol is reacted with pentanoic acid in the presence of an acid catalyst, what would be the expected major product?

Possible Answers:

Pentene

Butanoic acid

Butene

Butyl pentanoate

Correct answer:

Butyl pentanoate

Explanation:

To answer this question, it's important to consider what types of molecules are reacting. The pentanoic acid is a carboxylic acid, and the butanol is an alcohol. When carboxylic acids are reacted with alcohols in the presence of an acid catalyst, the result is an ester. 

Example Question #43 : Reactions By Reactant

Noname02

What is the product of the given reaction?

Possible Answers:

6

5

Noname04

Noname03

Noname01

Correct answer:

Noname03

Explanation:

This is a basic Claisen condensation reaction in which the  functions to take off the acidic hydrogen (between the ketone and the ester) and then the same molecule can attack a carbonyl carbon to yield Noname03.

The attack at the ester carbonyl leads to the leaving of  group.

Example Question #49 : Reactions By Reactant

What is the product of the following reaction?

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Screen shot 2015 11 13 at 1.56.10 pm

Possible Answers:

II only

I and II

IV only

II and III

Correct answer:

II and III

Explanation:

Treatment of ethyl acetate with methoxide will yield the enolate ion (II). However, side trans-esterification reactions will also result in formation of product III.

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