Photoinduced Cobalt-Catalyzed Carbonyl Umpolung Alkenylation

Herein we introduce a cobalt-catalyzed umpolung strategy for radical carbonyl alkenylation. This method provides an alternative pathway for producing Grignard-type products from (hetero)aryl vinyl bromides and aliphatic aldehydes without pre-functionalization. The method is distinguished by its broad substrate scope, mild reaction conditions, and simple catalytic system. Upon specific activation of the carbonyl group with AcI, a cobaloxime complex catalyst facilitates the selective reduction of the resulting α-oxy iodide through an atom transfer process.