Anion-Tuning of Organozincs Steering Cobalt-Catalyzed Radical Relay Couplings

A multicomponent sulfonylarylation reaction via cobalt-catalyzed alkene difunctionalizations with sulfonyl chlorides and OPiv-supported organozinc reagents was reported. Herein, anion-coordination played a critical role in the chemical property modification of organozinc reagents. Changing the anions of organozincs from halides (Cl, Br, and I) to pivalate (OPiv) resulted in a very different reactivity. OPiv-supported organozinc reagents steered the success of cobalt-catalyzed carbosulfonylation of alkenes, while halide-supported organozincs preferred to direct sulfonylation. Detailed mechanistic studies demonstrated that the OPiv-coordination results in lower reducibility of arylzinc pivalates, thereby enabling the in situ formation of catalytically relevant Co(I) species as the active catalyst. Density functional theory calculations suggested that the carbosulfonylation of alkenes involves a Co(I/II/I) manifold. Hence, ubiquitous sulfonyl chlorides, readily accessible alkenes, 1,3-dienes, and polyfunctionalized organozinc pivalates successfully underwent a regio- and stereoselective carbosulfonylation process through a radical relay pathway, thus realizing sequential functional group installation on both sides of the double bond.