Some experiments on the Smith reaction

Three possible mechanisms for the Smith reaction, the base-catalysed condensation of acetophenone and benzoin to desylacetophenone, were considered but no evidence was obtained for two of them. The third mechanism, involving an aldol condensation, dehydration, enolate formation, and reprotonation at a different site, accounted for the products formed in the reactions of two unsymmetrical benzoins with acetophenones, provided an equilibrium existed between the stable and labile forms of the benzoins under the reaction conditions. Deoxybenzoins and 1,4-diketones required for product identification were synthesized.