A visible light-induced palladium-catalyzed oxidative C–H alkylation of oximes has been developed. This mild protocol allows for an efficient atom economical C–C bond construction of alkyl-substituted oximes. A broad range of primary, secondary, and tertiary alkyl bromides and iodides, as well as a range of different formaldoximes, can efficiently undergo this transformation. The method features visible light-induced generation of nucleophilic hybrid alkyl Pd radical intermediates, which upon radical addition at the imine moiety and a subsequent β-hydrogen elimination deliver substituted imines.

Dual light-excited ketone/transition-metal catalysis is a rapidly developing field of photochemistry. It allows for versatile functionalizations of C–H or C–X bonds enabled by triplet ketone acting as a hydrogen-atom-abstracting agent, a single-electron acceptor, or a photosensitizer. This review summarizes recent developments of synthetically useful transformations promoted by the synergy between triplet ketone and transition-metal catalysis.1 Introduction2 Triplet Ketone Catalysis via Hydrogen Atom Transfer2.1 Triplet Ketones with Nickel Catalysis2.2 Triplet Ketones with Copper Catalysis2.3 Triplet Ketones with Other Transition-Metal Catalysis3 Triplet Ketone Catalysis via Single-Electron Transfer4 Triplet Ketone Catalysis via Energy Transfer5 Conclusions