Electrochemical Reduction of Beta‐Ketoesters: The Tafel Rearrangement

Abstract

The electrochemical reduction of ethyl α‐butylacetoacetate at a lead cathode in aqueous sulfuric acid formed n‐octane, 2‐heptanone, 2‐octanol, 3‐octanol, 2‐octanone, 3‐octanone, 2,3‐octanedione, ethyl caproate, and erythro‐ andthreo‐ethyl α‐n‐butyl‐β‐hydroxybutyrate. These products indicate that the Tafel Rearrangement proceeds through a cyclopropane intermediate. Studies of the reduction of 2‐methyl‐2‐carbethoxycyclohexanone, 2,5‐dicarbethoxy‐cyclohexane‐1,4‐dione, and 2,5‐dibenzyl‐2,5‐dicarbethoxycyclohexane‐1,4‐di‐one found that this method was not suitable for the preparation of cycloheptane and cyclooctane derivatives.