Synthesis of glycofuranosides from S-glycofuranosyl dithiocarbonates (xanthates) and dithiocarbamates

Coupling reactions between an anomeric mixture of S-ribofuranosylN,N-diethyldithiocarbamate (1b) as the donor and 1,2:3,4-di-O-isopropylidene-α-d-galactopyranose or 1,6-anhydro-3,4-O-isopropylidene-β-d-galactopyranose as the acceptor in the presence of silver triflate afforded β-d-ribofuranosyl disaccharides in good yield. Application of this glycosidation methodology for the synthesis of alkylglycofuranoside derivatives of d-xylofuranose and l-arabinofuranose resulted in the 1,2-trans configurated products with moderate to high stereoselectivity.