Chapter 19, Problem 1PP

PRACTICE PROBLEM 19.1

(a) Write a mechanism. for all steps of the Claisen condensation that take place when ethyl propanoate reacts with ethoxide ion.

(b) What products form when the reaction mixture is acidified?

Interpretation Introduction

Interpretation: The mechanism for all the steps of Claisen condensation when ethyl propanate reacts with ethoxide ion is to be written and when the reaction mixture acidified the product of the reaction is to be determined.

Concept introduction:

The Claisen condensation is the carbon-carbon bond forming reaction and important for the preparing $\beta -\text{Keto ester}$.

In Claisen condensation ester of one molecule adds to the carbonyl carbon of the another molecule and formation of $\beta -\text{Keto ester}$ takes place.

Answer to Problem 1PP

Solution:

(a)

(b)

Explanation of Solution

The mechanism for the reaction between ethylproponate and ethoxide ion is as follows:

Step 1

Step 2

Step 3

(b)

When the reaction mixture is acidified the reaction takes place is as follows;

Hence, the product formed when the reaction mixture acidified is as follows;