The Preparation ofO-Trifluoromethyl Carbohydrates

A simple method for the preparation of O-tri-fluoromethyl carbohydrate derivatives is reported. Carbohydrate derivatives bearing excellent leaving groups can react with tris(dimethylamino)sulfonium trifluoromethoxide (TAS+CF3-O-) to afford trifluoro-methoxy-substituted compounds along with varying amounts of the corresponding deoxyfluoro products. Primary and secondary triflates afford the corresponding trifluoromethyl ethers. Displacement at a secondary center occurs with complete inversion of configuration. Glucosyl bromides react to form mixtures of trifluoromethyl glucosides and glucosyl fluorides.