Dual Nickel/Photoredox-Catalyzed Asymmetric Carbosulfonylation of Alkenes

An asymmetric three-component carbosulfonylation ofalkenes ispresented here. The reaction, involving the simultaneous formationof a C-C and a C-S bond across the pi-system, usesa dual nickel/photoredox catalytic system to produce both beta-aryland beta-alkenyl sulfones in high yields and with excellent levelsof stereocontrol (up to 99:1 er). This protocol exhibits a broad substratescope and excellent functional group tolerance and its synthetic potentialhas been demonstrated by successful applications toward pharmacologicallyrelevant molecules. A broad array of control experiments supportsthe involvement of a secondary alkyl radical intermediate generatedthrough radical addition of a sulfonyl radical to the double bond.Moreover, stoichiometric and cross-over experiments further suggestan underlying Ni(0)/Ni-(I)/Ni-(III) pathway operative in these transformations.