Photoinduced Copper-Catalyzed Enantioselective Allylic C(<i>sp</i>³)–H Oxygenation of Acyclic Terminal Olefins Enabled by SphenBOX

Although the copper-catalyzed allylic C(sp³)-H oxygenation (Kharasch-Sosnovsky reaction) is a powerful transformation known for over a half century, its enantioselective version has been developed with drawbacks. High enantioselectivity was not achieved for acyclic terminal olefins and tertiary C-H bonds. Here we have addressed these long-standing challenges enabled by the design of new SphenBOX ligands. When combined with photocatalysis, a range of valuable allylic esters can be obtained directly from terminal olefins and carboxylic acids with high efficiency, regioselectivity, and enantioselectivity. Unprecedented enantioconvergent oxygenation of allylic tertiary C(sp³)-H bonds is demonstrated, allowing construction of quaternary stereocenters with high enantioselectivity. Structural analysis indicates that SphenBOX features a compact chiral pocket that may contribute to its superior performance.