Glycosylation with derivatives of phenyl 2-azido-2-deoxy-1-seleno-α-d-gluco- and -α-d-mannopyranosides

Glycosylation of primary (3-trifluoroacetamidopropanol) and secondary (methyl 2,3- O -isopropylidene-α- l -rhamnopyranoside) alcohols with phenyl 3,4,6-tri- O -acetyl-2-azido-2-deoxy-1-seleno-α- d -glucopyranoside in the presence of N -iodosuccinimide and trimethylsilyl triflate in diethyl ether afforded the corresponding 2-azido-2-deoxyglu-cosides in rather high yields and with good α-stereoselectivity (α:β = 3−5:1). Similar glycosylation with phenyl 3,4,6-tri- O -acetyl-2-azido-2-deoxy-1-seleno-α- d -manno-pyranoside resulted exclusively in α-linked 2-azido-2-deoxymannosides.