Functional group tolerance in organocatalytic regioselective acylation of carbohydrates.

Organocatalytic regioselective acylation of mono- and disaccaharides with various functionalized acid anhydrides has been developed. Acylation of octyl beta-D-glucopyranoside with acid anhydrides derived from alpha-amino acids, cinnamic acid, and gallic acid took place at C(4)-OH with 67-94% regioselectivity in the presence of catalyst 1. Regioselective acylation of disaccharides with functionalized acid anhydrides was also achieved with 78-94% selectivity. Especially, a disaccharide with seven free hydroxy groups (X = OH, R' = H) underwent acylation at C(4)-OH with 78% regioselectivity in the presence of 1. Thus, functional group tolerance in the regioselective acylation catalyzed by 1 was found to be high.