Electrochemical Chemo- and Regioselective Reduction of Vicinal Diketones to α-Hydroxy Ketones.

α-Hydroxy ketones are valuable motifs in bioactive molecules and versatile synthetic intermediates, yet their selective preparation from vicinal diketones remains challenging due to issues of chemoselectivity, regioselectivity, and sustainability. Herein, we report an electrochemically driven strategy for the chemo- and regioselective reduction of vicinal diketones to α-hydroxy ketones under mild, sustainable conditions, avoiding precious metals and stoichiometric reductants. Potential-controlled, stepwise electron transfer effectively suppresses over-reduction. The protocol displays broad substrate scope, high functional-group tolerance, and predictable regioselectivity dictated by electronic effects, and is applicable on gram scale as well as to the concise synthesis of a CAI-1 analogue. Mechanistic studies support a radical-anion/enolate pathway, with methanol serving as the proton source.