Stereoselective gem-Difunctionalization of Diazo Compounds with Vinyl Sulfoxonium Ylides and Thiols via Metalloradical Catalysis

Multicomponent reactions that involve carbenes with nucleophiles and electrophiles have demonstrated broad applications in synthetic chemistry. However, because of the high reactivity of transient carbenes, reactions involving two carbene precursors with the nucleophile in the presence of a metal catalyst remain unexplored. Herein, a three-component stereoselective gem-difunctionalization of diazo compounds with thiols and vinyl sulfoxonium ylide is disclosed via Co(II)-based metalloradical catalysis. The key aspect of the present strategy is to exploit the intrinsic difference in the reactivity of vinyl sulfoxonium ylides and diazo compounds with thiol and metal catalysts. The present Doyle–Kirmse rearrangement of a sulfonium ylide involves a convergent assembly of two in situ-generated intermediates, such as allyl sulfide and α- metalloalkyl radical complex, to provide expeditious access to tertiary sulfide scaffolds. Combined experimental and quantum chemical calculations unveil the intricate mechanism of this three-component reaction. Furthermore, theoretical studies on noncovalent interactions of selectivity-determining transition states explain the origin of the experimentally obtained diastereoselectivity.