Simplifying Access to 3,4-Di-O-acetyl-1,5 anhydro-2,6-dideoxy-d-lyxo-hex-1-enitol (3,4-Di-O-acetyl-d-fucal)*

N-Acetyl-d-fucosamine (d-FucNAc) is a rare sugar found in a variety of bacterial glycoconjugates. ¹ Chemical synthesis of their repeating units heavily relies on the use of orthogonally protected d-FucNAc-derived building blocks, which are available from diverse precursors. ² Azidonitration of the title 3,4-di-O-acetyl-D-fucal^2b,3 (3,4-di-O-acetyl-1,5-anhydro-2,6-dideoxy-d-lyxo-hex-1-enitol) has been routinely used in this laboratory to produce large quantities (>20.0 g) of d-fucosamine and derivatives thereof. Accessing the title compound ³ on a large scale from commercially available d-fucose is prohibitively expensive. We have developed a convenient, six-step procedure to produce this valuable compound in 34%–40% overall yield, starting from commercially available 1,2:3,4-di-O-isopropylidene-d-galactose.