Efficient Palladium(0)-Catalyzed Synthesis of Alkenyl 1-Thioglycosides and Thiodisaccharides

ABSTRACT

Unsaturated thiodisaccharides are obtained in good yields by alkylation of ethyl α-O-?²-glycosides, having a leaving group at C-4, with various thiocarbohydrates in the presence of a catalytic amount of palladium(0). The reaction is regio- and stereospecific for the α-erythro enoside, and only stereospecific in the case of the α-threo enoside, alkylation occurring at C-4 and C-2. In all cases, only the β-anomer is formed.