Indium tribromide-catalyzed highly stereoselective synthesis of alkynylsugars

Glycals react smoothly with alkynylsilanes in the presence of a catalytic amount of indium tribromide under mild reaction conditions to afford the corresponding alkynyl sugars in excellent yields with high α-selectivity. Alkynylation of 3,4-di-O-acetyl-d-xylal with alkynylsilanes afforded 1,4-anti adducts exclusively.