Enantioselective Synthesis of Allylic Sulfones via Rhodium-Catalyzed Direct Hydrosulfonylation of Allenes and Alkynes.

A highly regio- and enantioselective hydrosulfonylation using commercially available sodium sulfinates is reported, providing the first direct asymmetric rhodium-catalyzed hydrosulfonylation of allenes/alkynes to synthesize chiral allylic sulfones. Ligand screening studies demonstrated the indispensable role of the C 1 -symmetric P,N-ligand ( R ax , S , S )-StackPhim for achieving both high regioselecitivity (>20:1) and enantioselectivity (up to 97% ee). Notably, the operationally simple method and mild conditions allow for the rapid preparation of chiral allylic sulfones with a wide scope of functional groups. Moreover, the use of sodium tert -butyldimethylsilyloxymethanesulfinate enables the collective synthesis of various chiral sulfone derivatives after simple transformations of the protected hydroxymethyl product.