Benzyl Bromide → 2,5-anhydro-3,4,6-tris-O-(phenylmethyl)-D-mannose

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Reaction Steps

According to Flowchart C, 2,5-anhydro-D-mannose 24, is protected as the dimethyl acetal 25 which is reacted with sodium hydride in dimethylformamide, followed by benzyl bromide giving 2,5-anhydro-3,4,6-tris-O-(phenylmethyl)-D-mannose, dimethyl acetal 26. Compound 26 is treated with tetrafluoroboric acid in acetonitrile giving 2,5-anhydro-3,4,6-tris-O-(phenylmethyl)-D-mannose 27 which is reacted with diphenyl triphenylphosphoranylidenemethylphosphonate in toluene at reflux, giving 3,6-anhydro-1,2-dideoxy-1-(diphenoxyphosphinyl)-4,5,7-tris-O-(phenylmethyl)-D-manno-hept-1-enitol 28. Compound 28 is hydrogenated over palladium on carbon in methanol and acetic acid, giving 3,6-anhydro-1,2-dideoxy-1-(diphenoxyphosphinyl)-D-manno-heptitol 29, which is reacted with diphenyl chlorophosphate in pyridine, giving 3,6-anhydro-1,2-dideoxy-1-(diphenoxyphosphinyl)-D-manno-heptitol, 7-(diphenyl phosphate) 30, which is then hydrogenated with platinum oxide, giving the product 3,6-anhydro-1,2-dideoxy-1-phosphono-D-manno-heptitol, 7-(dihydrogen phosphate) 31. ##STR11##

Provenance & Evidence