Regioselective Benzoylation of 4,6-O-Benzylidene Acetals of Glycopyranosides in the Presence of Transition Metals.

The benzoylation of 4,6-O-benzylidene acetals of α-D-glucopyranosides and α-D-mannopyranosides with benzoic anhydride in the presence of (F3C-COO)2Cu gives 2-benzoates in good yields with high regioselectivity.