The first asymmetric synthesis of alpha-sulfanylphosphonates.

[reaction: see text] Diastereoselectivity of up to 88% was achieved for the synthesis of an alpha-mercapto gamma-unsaturated phosphonate using the readily available chiral dimenthylphosphonyl ester group and a carbanionic [2,3]-sigmatropic rearrangement. Absolute configuration of the newly formed chiral center of this nonracemic thiol was determined, and the corresponding phosphono thiolane and thiolane S-oxide were also stereoselectively prepared.