THE REGIOSELECTIVITY OF DIBUTYLSTANNYLENE-MEDIATED OXIDATION OF METHYL 3',4'-O-ISOPROPYLIDENE-α- AND β-LACTOSIDE. A NEW SYNTHESIS OF N-ACETYLLACTOSAMINE

Article abstract of DOI:10.1016/S0040-4020(01)86192-5

The dibutylstannylene-mediated oxidation of methyl 3',4'-O-isopropylidene-α-lactoside (1) under different conditions using bromine as oxidizing agent has been investigated.The regioselectivity of this reaction strongly depends on the solvent and the nature of the added base.The 2-keto derivative, isolated as the corresponding methyloximino (10) or benzyloximino (13) derivatives, is the only oxidation product when acetonitrile is used as solvent and tributyltin methoxide as base.The oxidation of methyl 3',4'-O-isopropylidene-β-lactoside (5) under the same conditions results in regioselective oxidation at C-3.The simple regioselective oxidation of the α-anomer (1) leads, after hydrogenation of the oximes (10 and 13) derived from the resulting 2-keto derivative, to lactosamine derivatives in a simple and convenient manner.