Enantioselective\nSynthesis of Benzylic Boronic Esters\nvia Photoredox/Nickel-Catalyzed Multicomponent Cross-Couplings

As a class of versatile building blocks, chiral benzylic\nboronic\nesters are important intermediates employed in modern organic chemistry.\nWe describe herein the first stereoconvergent multicomponent cross-coupling\nreaction of vinyl boronates, alkyltrifluoroborates, and aryl halides\nthrough a dual photoredox/nickel catalysis methodology. This synergistic\nplatform permitted the benign construction of various enantioenriched\nbenzylic boronic esters with broad substrate tolerance and moderate\nto excellent enantioselectivity (up to 98:2 <i>er</i>) from\ncommercially available starting materials. Moreover, experimental\nand computational studies shed light on the nickel catalytic transformation\nand the origin of the enantioselectivity.