Asymmetric α-Vinylation of β-Ketocarbonyls with Alkynes by Dual Photoredox/Nickel Catalysis and Hydrogen Atom Transfer

Abstract Despite significant progress in two-electron asymmetric α-vinylation of carbonyl compounds with activated alkynes, extending this methodology to less reactive or unactivated alkynes remains challenging due to the polarity mismatch in these ionic processes. Herein, we report an efficient visible-light-induced direct asymmetric α-vinylation of β-ketocarbonyls with commercially available simple alkynes by dual photoredox/nickel Lewis acid catalysis under hydrogen atom transfer (HAT) mediation. This transformation features the catalytic photogeneration of a chiral nickel-bound α-carbonyl radical that undergoes stereoselective addition to alkynes. The resulting vinyl radical species engages in a rapid HAT process with thiophenol (ArSH), ensuring high regioselectivity, stereoselectivity, and Z/E selectivity. This protocol circumvents the need for prefunctionalized vinyl reagents, exhibits broad functional group tolerance, and provides efficient access to enantioenriched alkenes bearing all-carbon quaternary stereocenters.