Substituent effects on the regioselectivity of enzymatic acylation of 6-O-alkylglycopyranosides using Pseudomonas cepacia lipase

The regioselectivity of acylation of a range of 6-O-protected glycosides using Pseudomonas cepacia lipase in vinyl acetate was investigated. In general, α-glycosides were acylated at the O-2 position and β-glycosides were acylated at the O-3 position. The effects of varying the size/hydrophobicity of the O-6 and anomeric substituents on the regioselectivity of the reaction are discussed in terms of the binding of the substrate in the active site of the enzyme.