O-Peracetylated methyl 3-( d-glycopyranosylthio)propanoates of β- d- gluco, and α- and β- d- galacto configurations were oxidized to the corresponding S,S-dioxides (sulfones) by Oxone ® or MCPBA. Oxidation of the β- d- gluco derivative with H 2O 2/Na 2WO 4 gave the corresponding S-oxide (sulfoxide). DBU-induced elimination of methyl acrylate from the β- d- gluco and β- d- galacto configured S,S-dioxides (sulfones) gave O-peracetylated β- d-glycopyranosyl-1- C-sulfinates which, on treatment with H 2NOSO 3H, furnished the corresponding β- d-glycopyranosyl-1- C-sulfonamides. Radical-mediated bromination of the protected methyl 3-(β- d-glycopyranosylthio)propanoate S,S-dioxides gave mixtures of 1- C- and 5- C-bromoglycosyl compounds. Similar brominations of the O-peracetylated β- d-glycopyranosyl-1- C-sulfonamides resulted in the formation of α- d-glycopyranosyl bromides and 1- C- and 5- C-bromoglycosyl sulfonamides. A rationale for these observations was proposed. Methyl 3-(β- d-glucopyranosylthio)propanoate, its S,S-dioxide, and β- d-glucopyranosyl-1- C-sulfonamide proved inefficient when tested as inhibitors of rabbit muscle glycogen phosphorylase b.