Functionalized C-Glycosyl Compounds. III. Reaction of Tertiary Nucleophiles with Unsaturated Carbohydrates. Mechanism of the Anomerization |
| |
| Authors: | Brahim Chaguir Mohamed Brakta Véronique Bolitt Paul Lhoste Denis Sinou |
| |
| Institution: | Laboratoire de Synthèse Asymétrique, associé au CNRS , ESCIL, Université Claude Bernard , 43 bd du 11 Novembre 1918, 69622, Villeurbanne, Cédex, France |
| |
| Abstract: | Abstract Phenyl 2, 3-dideoxy-4, 6-di-O-benzyl-D-erythro-hex-2-enopyranoside 1α (or 1β) is alkylated regio- and stereospecifically at the anomeric center by stabilized tertiary nucleo-philes in the presence of Pd(0) as a catalyst, leading to the C-glycoside of α- (or β-) configuration. The observed loss of stereoselectivity using secondary stabilized nucleophiles is mainly due to a retro Michael reaction. The assignment of the α- (or β-) configuration at the anomeric center was accomplished using 13C NMR and NOE experiments. |
| |
| Keywords: | |
|
|
