α/β-Stereo- and diastereoselective glycosylation with n -pentenyl glycoside donors, promoted by N -iodosuccinimide and catalyzed by chiral Brønsted acid

A method involving stereoselective glycosylation catalyzed by (+)-isomenthol ester of pentacarbomethoxycyclopentadiene as a chiral Brønsted acid, with -pentenyl glycosides in the presence of -iodosuccinimide as the promoter is described; this method offered a chiral recognition of racemic substrates.