SYNTHESIS OF 2,3-ANHYDRO GLYCOSYL PHOSPHONATES

The synthesis of dimethyl tyl-2,3-anhydro-alpha-D-mannopyranosylphosph onates and the corresponding alpha- and beta-allo derivatives is descr ibed. Dimethyl -dideoxy-D-erythro-hex-2-enopyranosylphosphonates, alth ough unreactive towards normal epoxidizing agents (3-chloroperoxybenzo ic acid, trifluoroperoxyacetic acid, etc), underwent smooth epoxidatio n with hydrogen peroxide in the presence of sodium tungstate or dodeca tungstophosphoric acid. An interesting regiospecific deacetylation of the 4-acetate occurred under these conditions. The structures of these anhydro glycosyl phosphonates were determined by H-1 and C-13 n.m.r. spectroscopy, and confirmed by X-ray structural analysis in the case o f dimethyl etyl-2,3-anhydro-alpha-D-mannopyranosylphosphonate and of d imethyl cetyl-2,3-anhydro-beta-D-allopyranosylphosphonate.