Enantioselective Three-Component Radical Alkene Diazomethyl-Cyanation Enabled by Copper/Photoredox Dual Catalysis

Radical-mediated alkene dicarbofunctionalizations enable
the construction
of molecular complexity and the exploration of diverse C(sp3)-rich scaffolds. However, catalytic enantioselective three-component
versions are underdeveloped. Herein, we report a copper/photoredox
dual-catalyzed enantioselective alkene diazomethyl-cyanation. The
key to the success is the selection of appropriate photocatalyst for
the generation of diazomethyl radicals from α-iodonium diazo
compounds and the introduction of a chiral bis(oxazoline) copper catalyst
for the radical-metal crossover process. This protocol constitutes
the asymmetric simultaneous incorporation of cyano and diazomethyl
moieties across an alkene, providing general access to enantioenriched
β-cyanodiazo compounds with tertiary or quaternary carbon stereogenic
centers under mild conditions.