Stereo- and Enantioselective Benzylic C-H Alkenylation via Photoredox/Nickel Dual Catalysis

A stereo- and enantioselective benzylic C-H alkenylation via photoredox/nickel catalysis is reported. Readily available alkylbenzenes and alkenyl bromides including complicated molecules undergo this cross-coupling reaction smoothly to afford chiral allylic compounds in up to 93% ee and >20/1 E/Z ratio under mild reaction conditions with good functional group tolerance. A triplet-energy-transfer-inhibiting strategy is developed for the stereoselective synthesis of alkenes under visible-light photocatalysis. The coordination pattern of nickel with chiral bis-imidazoline ligand has been illustrated based on nonlinear effect experiments and X-ray diffraction.

Automated summary

A stereo- and enantioselective benzylic C-H alkenylation via photoredox/nickel catalysis has been developed, allowing for smooth cross-coupling reactions of readily available alkylbenzenes and alkenyl bromides, even with complicated molecules. The reaction conditions are mild with good functional group tolerance, yielding chiral allylic compounds with high ee and E/Z ratio. Additionally, a triplet-energy-transfer-inhibiting strategy has been developed for stereoselective synthesis of alkenes under visible-light photocatalysis, with the coordination pattern of nickel with chiral bis-imidazoline ligand elucidated based on experiments and X-ray diffraction.