Stereochemical factors in the cathodic pinacolisation of acetophenone at a mercury pool

Abstract

The racemic : meso ratio for the pinacol product from the reduction of acetophenone at a mercury cathode has been determined as a function of solvent composition and electrolyte type. It is proposed that the sterochemistry of the coupling process is strongly influenced by ion pairing when anionic intermediates are involved, and by hydrogen bonding in the case of neutral intermediates. The ratio was as high as 12·5:1 using dry dimethylformamide containing lithium perchlorate as electrolyte.