Stereoselective synthesis of C-[2-S-(p-tolyl)-2-thio-beta-D-galactopyranosyl] compounds using the reaction of TolSCl adducts of D-galactal with C-nucleophiles.

Pyranosyl chlorides prepared in situ from tri-O-benzyl-D-galactal and TolSCl react with silyl enol ethers, allyltrimethylsilane, and vinyl ethers to give a mixture of beta-C-galacto and alpha-C-talopyranosides in a ratio of 19:1.