Double Diastereoselection, Regioselectivity, and the Importance of Donor-Acceptor Complementarity in the Stereoselectivity of Glycosylation Reactions

Glycosylation is a process involving the union of two chiral partners, a donor and an acceptor, and is therefore formally subject to double diastereodifferentiation. In this review, we discuss, through the presentation of suitable examples, double diastereoselection in glycosylation reactions based on the matched and mismatched concept. We also discuss the related but more widely appreciated concept of regioselective glycosylation of diols and illustrate through select examples how this may vary on the basis of donor and even promoter. Finally, we diverge from the usual course of representation of glycosylation stereoselectivity as a simple ratio, and also represent it in terms of diastereomeric excess to facilitate comparison with other branches of organic chemistry.