Efficient one-pot synthesis of 2-hydroxyethyl per-O-acetyl glycosides

Abstract

AbstractA class of stereo-isomerically-pure alkanediol monoglycosides, 2-hydroxyethyl per-O-acetyl pyranosides (IIIa-IIIf), was conveniently prepared by a one-pot reaction of per-O-acetylated pyranoses (Ia-If) and 2-(tert-butyldimethylsilyloxy)ethanol (II) with catalysis by BF3·OEt2. The α-(IIIa) or β-linked glycosides (IIIb-IIIf) with 1,2-trans-configuration were obtained from glycosyl donors with participation of the neighbouring 2-O-acetyl group. BF3·OEt2, along with hydrogen fluoride released from BF3·OEt2 under the experimental conditions used, facilitates the subsequent de-protection of siloxane to successfully afford 2-hydroxyethyl per-O-acetyl-pyranosides.