On Orthogonal and Selective Activation of Glycosyl Thioimidates and Thioglycosides: Application to Oligosaccharide Assembly
作者:Sophon Kaeothip、Alexei V. Demchenko
DOI:10.1021/jo201117s
日期:2011.9.16
Discrimination among S-thiazolinyl (STaz), S-benzoxazolyl (SBox), and S-ethyl anomeric leaving groups was achieved by fine-tuning activation conditions. Preferential glycosidation of a certain leaving group is determined neither by the strength of the activating reagent nor by the stability of the leaving group itself; instead, the type of activation plays the key role. The activation conditions established herein were applied to a sequential five-step synthesis of a hexasaccharide using six monosaccharide building blocks equipped with six different leaving groups.