Ligand-Controlled Copper-Catalyzed Regiodivergent Sulfonylation of Yne-Vinyl Allylic Esters with Sodium Sulfinates

Herein, we report the first ligand-controlled
copper-catalyzed
regiodivergent sulfonylation of yne-vinyl allylic esters with sodium
sulfinates. The practicality and attractiveness of this protocol are
showcased using readily available starting materials, mild reaction
conditions, good regio- and stereoselectivities, and a broad substrate
scope. A series of controlled experiments identified a copper divinyl-allenylidene
complex as the key intermediate in this reaction. Density functional
theory calculations delineate distinct mechanistic pathways for each
nucleophilic addition step and elucidate their regioselectivity.