p-tert-Butyl Groups Improve the Utility of Aromatic Protecting Groups in Carbohydrate Synthesis

Aromatic protective groups are widely used in carbohydrate synthesis owing to their numerous merits. However, they unpredictably make certain compounds insoluble in organic solvents owing to their π-stacking abilities. It was found that introducing a tert-butyl group onto the aryl moiety improves the solubility of highly insoluble carbohydrate derivatives, such as those of N-acetylglucosamine. In this study, tert-butyl-substituted aromatic protecting groups are demonstrated to work as well as the original unsubstituted form, while improving the efficiency of glycosylations.