Chapter 23.SE, Problem 61AP

Interpretation Introduction

Interpretation:

The difference in reactivity between ethyl acetoacetate (cleaves at 150°C) and ethyl dimethylacetoacetate (cleaves at room temperature) with ethoxide ion is to be explained.

Concept introduction:

The attack of the base on the carbonyl carbon of the ester and subsequent elimination of ester and protonation of the anion leads to products in a reverse Claisen reaction. However if the ester has acidic α-hydrogen atoms, the base can abstract it giving a stable resonance stabilized anion. In such cases the reverse Claisen reaction will not takes place readily at room temoerature.

To explain:

The difference in reactivity between ethyl acetoacetate (cleaves at 150°C) and ethyl dimethylacetoacetate (cleaves at room temperature) with ethoxide ion.