Synthesis of 5-deoxy-5-hydroxyphosphinyl-d-mannopyranoses

The title sugar analogues (13) were synthesized by starting with known methyl (E)-5,6-dideoxy-2,3-O-isopropylidene-6-nitro-α-d-lyxo-hex-5-enofuranoside (5a) in six steps through the key intermediate, methyl 5-deoxy-5-dimethoxy-phosphinyl-2,3-O-isopropylidene-α-d-mannofuranoside 8a). The products (13) were converted into the corresponding penta-O-acetyl-5-methoxyphosphinyl derivatives (14), whose structures and conformations (mostly ⁴C₁) were established by spectroscopy.