Intramolecular 1,8-hydrogen atom transfer. Stereoselectivity of the hexopyranos-5'-yl radical reactions in Hex p-(1-->4)-Hex p disaccharide systems.
The stereoselective reduction of hexopyranos-5'-yl radicals in alpha-D-Hex p-(1-->4)-D-Hex p disaccharide models is described. These radicals are generated from a 6-O-yl radical located in the other monosaccharic unit through a 1,8-hydrogen atom transfer. The reaction, which is strongly influenced by steric and stereoelectronic effects, permits in some cases the transformation of alpha-D-Hex p-(1-->4)-D-Hex p into beta-L-Hex p-(1-->4)-D-Hex p disaccharides in a single step with high diastereoselectivity.
Martín
Angeles
A
Instituto de Productos Naturales y Agrobiología del C.S.I.C., Carretera de La Esperanza 3, 38206 La Laguna, Tenerife, Spain. angelesmartin@ipna.csic.es
Pérez-Martín
Inés
I
Quintanal
Luís M
LM
Suárez
Ernesto
E
D004187:Disaccharides / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry*; D006601:Hexoses / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D013237:Stereoisomerism
D004187:Disaccharides; D005609:Free Radicals; D006601:Hexoses; D006859:Hydrogen