Microwave-assisted stereospecific intramolecular rearrangement of (1→6)-linked disaccharides catalyzed by Mo(VI)

Three (1→6)-linked disaccharides, melibiose, isomaltose and palatinose, were converted into their isomers via intramolecular rearrangement catalyzed by Mo(VI). The reaction proceeded with excellent stereoselectivity. Product disaccharides, α-d-galactopyranosyl-(1→6)-d-mannose, α-d-glucopyranosyl-(1→6)-d-mannose and α-d-glucopyranosyl-(1→6)-2-C′-(hydroxymethyl)-d-ribose were structurally characterized by NMR and MS spectroscopy. This contribution highlights the remarkable advantages of Mo(VI) catalysis and beneficial effects of microwave irradiation in oligosaccharide synthesis.