Azido-phenylselenylation of 3-O-benzyl-2-deoxy-5,6-O-isopropylidene-D-arabino-1,4-anhydro-hex-1-enitol: Convenient preparation of 2-azido-2-deoxy-D-glucofurano- and glucopyranoside donors.

Azido-phenylselenylation of 3-O-benzyl-2-deoxy-5,6-O-isopropylidene-D-arabino-1, 4-anhydrohex-1-enitol (1) afforded an alpha/beta mixture of phenyl 2-azido-3-O-benzyl-2-deoxy-5,6-O-isopropylidene-1-seleno-D-glucofuranoside (2) together with a small amount of 3-O-benzyl-2-deoxy-5,6-O-isopropylidene-2-phenylseleno-D-glucofur?anosyl azide (3). Acetolysis of the mixture afforded 2-azido-2-deoxy-glucofuranosyl donor (4). Hydrolysis of the acetal group and of the selenoglycoside 2 followed by acetylation and removal of the anomeric acetate provide an efficient access to 5,6-di-O-acetyl-2-azido-3-O-benzyl-2-deoxy-D-glucopyranose (8), synthetic equivalent of D-glucosamine.