A new efficient glycosylation method employing glycosyl pentenoates and PhSeOTf

The PhSeOTf promoted glycosylations of various glycosyl acceptors with mannosyl pentenoates and glucosyl pentenoates as glycosyl donors afforded corresponding disaccharides in high yields. And the present glycosyl pentenoates/PhSeOTf method showed that the complete α-selective mannosylation of secondary alcohol acceptors was achieved with 2,3,4,6-tetra-O-benzyl-d-mannopyranosyl pentenoate to give α-disaccharides in good yields.