Catalyzed by PhSe(O)OH/Cu(OAc)2, sp3-C–H alkylation of bromomethylene ketones produced useful α-carbonyl acetals under mild conditions. Bromo-containing substrates could release HBr during the reaction, avoiding the use of acidic additives.

Se and Cu synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize α‐keto acetals directly. Using O2 as oxidant and alcohol as solvent and alkoxylation reagent, the reaction is practical from industrial viewpoint. Mechanistic studies revealed that Cu promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn‐elimination regenerating the catalytically active Se species.