Direct Glycosylation of Unprotected and Unactivated Carbohydrates under Mild Conditions

Ligand exchange acetalization of acetals in the presence of catalytic amounts of mandelic acid and titanium tert-butoxide is reported. This transformation is successfully extended to glycosylation of unprotected and unactivated pentoses. Even unreactive pentoses such as D-arabinose or D-lyxose can be transformed by this new methodology into corresponding isopropyl glycosides.