Improved anomeric selectivity for the aroylation of sugars

By manipulating the solvent and using bulky TMEDA as a base, good yields and improved anomeric selectivities were obtained for the aroylation of d-glucose over similar esterifications using pyridine. The reaction has been extended to mannose and the β-anomer of pergalloylated mannose was predominantly obtained in one step by direct aroylation of the parent sugar.