Synthesis of aryl α-O-L-rhamnopyranoside by two-step reaction in one pot
The title compounds were conveniently synthesized by a phase transfer catalyzed approach in two steps and one pot using the rhamnopyranosyl chloride as key intermediate. The twostep one-pot procedure is more convenient and environmentally friendly, compared to the published synthetic routes. Besides, the structure-reactivity relationship and the plausible mechanism for this base-catalyzed glycosylation were discussed bymeans of the Hammett equation.
Glycosynthase with broad substrate specificity-an efficient biocatalyst for the construction of oligosaccharide library
A versatile glycosynthase (TnG-E338A) with strikingly broad substrate scope has been developed from Thermus nonproteolyticus β-glycosidase (TnG) by using site-directed mutagenesis. The practical utility of this biocatalyst has been demonstrated by the facile generation of a small library containing various oligosaccharides and a steroidal glycoside (total 25 compounds) in up to 100 % isolated yield. Moreover, an array of eight gluco-oligosaccharides has been readily synthesized by the enzyme in a one-pot, parallel reaction, which highlights its potential in the combinatorial construction of a carbohydrate library that will assist glycomic and glycotherapeutic research. Significantly, the enzyme provides a means by which glycosynthase technology may be extended to combinatorial chemistry.