A process for the preparation of an enantioenriched sulfone of formula (1), which comprises asymmetric hydrogenation of vinyl sulfone of formula (2)
wherein R1 and R2 are each independently a hydrocarbon group of less than 20 carbons atoms, optionally substituted at any position, or either of R1 and R3 is H, and X is a coordinating group, in the presence of a stereoselective chiral catalyst.