Regioselective Benzoylation of 4,6-O-Benzylidene Acetals of Glycopyranosides in the Presence of Transition Metals
摘要:
Benzoylation of 4,6-O-benzylidene acetals of glycopyranosides by benzoic anhydride in acetonitrile in the presence of Cu(CF3COO)(2) as a promoter gave 2-benzoates for alpha-D-glucopyranosides and alpha-D-mannopyranosides and 3-benzoates for beta-D-galactopyranosides in good yields with high regioselectivity. Benzoylation of 4,6-O-benzylidene acetals of glycopyranosides of D-galactose and D-mannose by benzoyl chloride in the presence of MoO2(acac)(2) as a catalyst in all studied cases led to regioselective 3-O-substitution.