Synthesis of a stable, storable and differentially protected acyclic precursor of D-amicetose and its conversion to 4-O-benzyl-protected D-amicetose

Two carbon chain homolgation of enantiopure four carbon erythro configured iodo derivative 5 with N-methoxy-N-methyl-2-phenylsulfonylacetamide 6 affords for the first time a stable and storable precursor 3 of D-amicetose in the acyclic form, wherein the sensitive aldehyde is masked as a Weinreb amide. The differential protection in this acyclic derivative offers all the potential to exclusively arrive at the pyranose form of the target dideoxy-sugar.