Chapter 5 Oligosaccharide Synthesis: From Conventional Methods to Modern Expeditious Strategies

Abstract

Abstract Although glycoscientists have learned over the years how to isolate certain classes of naturally occurring complex carbohydrates, the availability of pure natural isolates, remains inadequate to address the ongoing challenges. As a result, glycoscientists have turned to chemical synthesis for access to complex oligosaccharides and glycoconjugates. Efficient chemical synthesis of complex carbohydrates can yield significant quantities of the pure natural structures as well as unnatural mimetics that are often of interest. Traditional oligosaccharide synthesis, however, often requires extensive protecting‐group manipulations between each glycosylation step. Such additional manipulations increase the number of total synthetic steps and inevitably decrease the efficiency, as reflected in a dramatic drop in yield. This chapter classifies and discusses significant recent improvements that have emerged to address the drawbacks of the traditional approach. Expeditious new strategies effectively shorten the task of oligosaccharide assembly by minimizing the need for protecting‐group manipulations between glycosylation steps, or even purification of the intermediates. The excellent innovations surveyed here have already facilitated synthesis of complex oligosaccharides and glycoconjugates, and some representative examples are discussed herein.