13 The Controlled Synthesis of Carbohydrates

AbstractWhile the formation of the glycosidic bond is the key transformation in the synthesis of polysaccharides, a dominant class of biopolymer, the reaction is poorly understood and remains highly challenging to perform reliably and selectively in a laboratory setting. This is due to the numerous intermediates and competing mechanistic pathways present, all of which are extremely sensitive to the environmental conditions of the reaction. This sensitivity and irreproducibility is an excellent opportunity to take advantage of the inherent control over reaction conditions achievable in micro- and meso-flow reactors. In this chapter, the range of transformations performed under continuous-flow conditions related to the synthesis of carbohydrates, including glycosidic bond formation, functional-group manipulations, and multistep synthesis, are presented and discussed. The advantages gained in flow are highlighted and, where available, directly compared to the respective batch process.