A convenient synthesis of 1,2,4-Tri-O-acetyl-5-deoxy-5-[(R)- and (S)-ethylphosphino and phenylphosphino]-3-O-methyl-α,β-D- xylopranoses and their phosphinothioyl derivatives section

1,2,4-Tri-O-acetyl-5-deoxy-5-[(R)- and (S)-ethylophosphinyl]-3-O-methyl-α,β-D-xylopyranoses (8a - d) were prepared from 5-deoxy-5-[(R)- and (S)-(ethoxy)ethylphosphinyl]-1,2-O-isopropylidene-3-O-methyl-α-D- xylofuranoses in two steps. Reduction of 8a - d and their 5-(phenylphosphinyl) congeners with trichlorosi-lane-triethylamine in benzene smoothly afforded the corresponding title 5-deoxy-5-phosphino-D-xylopyranoses (9a - d and 14a - d) without causing inversion of the ring-phosphorus atom. Treatment of 9a - d and 14a - d with sulfur in benzene efficiently provided the corresponding (phosphinothioyl)-in-ring D-xylopyranoses. Structural and conformational assignments of these newly obtained compounds were made on the basis of mass and NMR (¹H and ³¹P) spectral data.