Synthesis of 1,2-cis-Configurated Glycosylphophonates

Article abstract of DOI:10.1002/hlca.19860690105

A synthesis of 1,2-cis-configurated, non-isosteric phosphonate analogues of aldose-1-phosphates is described.Treatment of 1-O-acyl-glycose 1, 7, 13, and 19 with trialkyl phosphite in the presence of trimethylsilyl trifluormethanesulfonate gave the 1,2-cis-configurated glycosylphosphonates 2, 4, 8, 10, 14, 16, 20, and 22 as the major anomers and the 1,2-trans-configurated glycosylphosphonates 3, 5, 9, 11, 15, 17, 21 and 23 as the minor anomers.The 1,2-cis-configurated phosphonates 4, 10, 16, and 22 were deprotected to give the (α-D-glucopyranosyl)phosphonate 6, the (β-D-mannopyranosyl)phosphonate 12, the (α-D-ribofuranosyl)phosphonate 18, and the (β-D-arabinofuranosyl)phosphonate 24, respectively, in high yields.The preferred formation of 1,2-cis-configurated phosphonates is explained by postulating an equilibrium between the anomeric phosphonium-salt intermediates (such as 25 and 26) and a stabilization of the cis-configurated salts through formation of pentacoordinated species (such as 28).