Concise Synthesis of P-Glycosyl Alkenylphosphonates and P,C-di and P,P,C tri-Glycosyl Phosphonates

A direct access to P-glycosyl-, P, P-di-glycosyl alkenylphosphonates and P, C-glycosyl phosphonates is described. The method involves the Horner reaction of an anion derived from P-monoglycosyl and P ¹, P′-diglycosyl methylenediphosphonates either on the exocyclic aldehyde group of carbohydrates or on the masked aldehydic form of the furanose hemiacetals. In this last case, the carbonyl olefination, followed by an intramolecular cyclization, leads to P,C-di and P,P,C-triglycosyl phosphonates.