Eschenmoser-Claisen Rearrangement

In 1964, the Swiss chemist Albert Eschenmoser reported that allylic or benzylic alcohols heated in the presence of N,N-dimethylacetamide dimethyl acetal in xylenes underwent a form of Claisen rearrangement. This generated a γ,δ-unsaturated amide with a high level of stereospecificity, and today this transformation has become known as the Eschenmoser-Claisen rearrangement.

This rearrangement typically occurs at lower temperatures, between 100-150°C, than other variants such as the Claisen rearrangement itself and is more (E)-selective.

During the first total synthesis of (±)-Stenine by D.J. Hart and colleagues, one of the key steps was an Eschenmoser-Claisen rearrangement that afforded a key amide intermediate in 93% yield.