Stereoselective C-glycosidation of d-fucose derivatives directed by the protective groups
作者:Omar Cortezano-Arellano、Camilo A. Meléndez-Becerra、Fernando Cortés、Fernando Sartillo-Piscil、Alejandro Cordero-Vargas
DOI:10.1016/j.carres.2014.04.005
日期:2014.7
Stereoselectivity in the C-glycosidation of lactones derived from D-fucose by following Kishi's method, which involves the addition of a nucleophile onto a carbohydrate-derived lactone and subsequent reduction of the lactol, was found to be reliant on the nature of the C2 and C3 protective groups. Lactones bearing TBDMS protecting groups selectively afford 1,3-trans products (alpha anomer), in which the stereoselective outcome is in apparent concordance with Woerpel's model. On the other hand, their benzylated congeners produce the 1,3-cis products (beta anomer) as the major diastereoisomers. The latter results suggest an abnormal behavior during the stereoselective nucleophilic substitution at the anomeric position of the benzylated lactones. (C) 2014 Elsevier Ltd. All rights reserved.