N-Nosyl as a stereoselectivity-improving and easily removable group in the O-glycosylation of D-allal and D-galactal-derived allyl aziridines. Stereospecific synthesis of 4-amino-2,3-unsaturated-O-glycosides

摘要

The glycosylation of alcohols, phenol, and partially protected monosaccharides with the diastereoisorneric D-allal and D-galactal-derived N-nosyl aziridines 2 alpha and 2 beta leads to the corresponding 4-N-(nosylamino)-2,3 -unsaturated-alpha-O- (6 alpha) and beta-O-glycosides and disaccharides (6 beta), respectively, in a stereospecific substrate-dependent O-glycosylation process. The N-(nosylamino) group of 6 alpha and 6 beta can easily be deprotected to give the corresponding 4-amino-2,3-unsaturated-O-glycosides 7 alpha and 7 beta, with an increased value to our glycosylation protocol. (c) 2007 Elsevier Ltd. All rights reserved.