Stereoselective synthesis of 2-deoxy-2-phenylselenenyl glycosides from furanoses: Implication of the phenylselenenyl group in the stereocontrolled preparation of 2-deoxy-ribo- and 2-deoxy-xylo-oligosaccharides

Identificador:  imarina:9284616

Handle: https://hdl.handle.net/20.500.11797/imarina9284616

Autors:  Boutureira, O; Rodríguez, MA; Benito, D; Matheu, MI; Díaz, Y; Castillón, S

Resum:
A series of 2-deoxy-2-phenylselenenyl-1-thioglycosides were evaluated as a class of glycosyl donors that provide access to 2-deoxyglycosides from furanoses. This short synthetic route involves olefination, selenonium ion mediated 6-endo cyclization and glycosylation reactions. The cyclization reaction proceeds with complete regio- and stereoselectivity, which are enhanced by employing 3,4-O-isopropylidene as a cyclic bifunctional protecting group. The implication of the phenylselenenyl group at C-2 in the stereocontrolled preparation of 2-deoxyoligosaccharides is discussed. Its presence gives some insights into the likely pathway of glycosylation reactions by using 2-deoxy-2-phenylselenenyl-1-thioglycosyl donors in comparison with the previously described 2-deoxy-2-iodo derivatives. We also demonstrated that the glycosylation of 2-deoxy-2-phenylselenenyl-1-thioglycosides is highly substrate dependent, as well as particularly effective in providing 2-deoxy-2- phenylselenenyl-?-D-gulo- and -?-D-allo-glycosides. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007.