Pd-Catalyzed Multicomponent Cross-Coupling of Allyl Esters with Alkyl Bromides and Potassium Metabisulfite: Access to Allylic Sulfones.

A Pd-catalyzed multicomponent cross-coupling of allyl esters with alkyl bromides to synthesize allylic sulfones by using KSO as a connector is first reported. The reaction displays a broad range of substrate generality along with excellent functional group compatibility and produces the products with high regioselectivity (only E). Furthermore, the biologically active molecules with a late-stage modification, including aspirin, menthol, borneol, and estrone, are also highly compatible with the multicomponent cross-coupling reaction. Mechanistic studies indicate that the process of SO insertion into the C-Pd bond was involved in this transformation.