Efficient stereocontrolled synthesis of C-glycosides using glycosyl donors substituted by propane 1,3-diyl phosphate as the leaving group

Abstract

α- and β-Glycosyl cyanides, per- O-acetyl-1,2- O-1-cyanoethylidenes and C-allyl glycopyranosides were efficiently prepared by treatment of 2,3,4-tri- O-acetyl-α,β- l-rhamno-, l-fuco- and 2,3,4,6-tetra- O-acetyl-α,β- d-galactopyranosyl propane-1,3-diyl phosphates with trimethylsilyl cyanide (TMSCN) and allyltrimethylsilane in the presence of trimethylsilyl triflate (TMSOTf). Similarly 2,3,4,6-tetra- O-benzyl-α,β- d-manno- and d-glucopyranosyl propane-1,3-diyl phosphates were employed in the synthesis of C-glycosides.