Stereoselective synthesis of C-[2-S-(p-tolyl)-2-thio-β-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 β-C-galacto and α-C-talopyranosides in a ratio of 19:1.