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.