title: Synthesis of l-Pyranosides by Hydroboration of Hex-5-enopyranosides Revisited.
abstract: Extensive study of the diastereoselective synthesis of l-pyranosides utilizing hydroboration of substituted exo-glucals (5-enopyranosides) obtained from d-sugars is presented. On the basis of this study we present the empirical rules describing the reaction stereoselectivity and the correlation between the yield of the l-ido product and the size of protecting groups used. Application of these guidelines revealed that the hydroboration of methyl 2,3-O-methyl-6-deoxy-α-d-xylo-hex-5-enopyranoside resulted in exclusive formation of l-ido product with high yield. This method can be successfully applied to the synthesis of l-iduronic acid being an essential component of anticoagulant drugs with diastereoselectivity superior to previously published protocols.
authors: Faculty of Chemistry, Jagiellonian University , Ingardena 3, 30-060 Krakow, Poland.
authors: Grzegorz
authors: G
authors: Łopatkiewicz
authors: Faculty of Chemistry, Jagiellonian University , Ingardena 3, 30-060 Krakow, Poland.
authors: Jacek
authors: J
authors: Mlynarski