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

A multicomponentsulfonylarylation reaction via cobalt-catalyzedalkene difunctionalizations with sulfonyl chlorides and OPiv-supportedorganozinc reagents was reported. Herein, anion-coordination playeda critical role in the chemical property modification of organozincreagents. 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-catalyzedcarbosulfonylation of alkenes, while halide-supported organozincspreferred to direct sulfonylation. Detailed mechanistic studies demonstratedthat the OPiv-coordination results in lower reducibility of arylzincpivalates, thereby enabling the in situ formation of catalyticallyrelevant Co(I) species as the active catalyst. Density functionaltheory calculations suggested that the carbosulfonylation of alkenesinvolves a Co(I/II/I) manifold. Hence, ubiquitous sulfonyl chlorides,readily accessible alkenes, 1,3-dienes, and polyfunctionalized organozincpivalates successfully underwent a regio- and stereoselective carbosulfonylationprocess through a radical relay pathway, thus realizing sequentialfunctional group installation on both sides of the double bond.