Synthesis of α-Chlorocarbonyls through Kharasch-Type Addition and Cotelomerization Driven by Photoredox/Cobalt Dual Catalysis

Abstract Here, we report a dual photoredox/cobalt catalytic system for synthesis of α-chlorocarbonyls through Kharasch-type addition and cotelomerization using readily available alkyl radical precursors, Michael acceptors, and collidine hydrogen chloride salts. This catalysis enables simultaneous installation of alkyl and chloride groups across Michael acceptors via alkyl radical addition to Michael acceptors followed by cobalt chloride-mediated halogen atom transfer to the α-carbonyl radicals. Notably, this platform tolerates various patterns of alkyl radical generation, such as single-electron reduction of redox active esters or an oxalate, and metal hydride-mediated hydrogen atom transfer to alkenes. These features enable rapid and programmable synthesis of α-chlorocarbonyl compounds from readily available materials.