Stereocontrolled glycosyl transfer reactions with unprotected glycosyl donors

A review is given on the methods of O-glycoside synthesis from anomerically activated glycosyl donors in which minimals or no hydroxyl protection is needed. Fisher glycosylation of alcohols is revisited over 100 years later and nature's pathways to glycoside synthesis are emulated albeit with limitations. The concept of remote activation in glycosyl transfer reactions as exemplified by the chemistry of O-unprotected 3-methoxy-2-pyridyloxy (MOP) glycosyl donors is also highlighted.