Copper-Catalyzed Remote Asymmetric Three-Component Sulfonylation Using SO2 as the Sulfur Source to Access Chiral Allylic Sulfones.

A copper-catalyzed enantioselective sulfonylation of yne-allylic esters with sulfur dioxide and cyclopropan-1-ols is reported. This three-component reaction proceeds via selective ε-addition of γ-keto sulfinate to copper-allenylidene intermediates, enabling efficient synthesis of chiral allylic sulfones under mild conditions. The protocol features high enantioselectivity (up to 96% ee), broad functional group compatibility, and good yields.