Structural analysis of 3-<i>C</i>-phosphonates, -phosphinates, and -phosphine oxides of branched-chain sugars

Abstract

A complete nmr study ( 1 H, 13 C, 31 P) of twelve 3-C-phosphonates, -phosphinates, and -phosphine oxide derivatives of 3-C-branched-chain pento- and hexo-furanoses is reported. For all compounds the configuration at C 3 is determined and, for oxaphospholanes 9 to 12, the configuration at the asymmetric phosphorus atom. The 3 T 2 conformation of the furanose ring of acyclic derivatives 1 to 8 and the conformationally rigid cis-fused oxaphospholane-furanose bicyclic systems of 9 to 12 have been used to study the 3 J PCCH vs. θ P . H and 3 J PCCC vs. θ P . C relationships which are specific to this series of compounds. The use of the ν P=O ir stretching frequency, δ 31 P chemical shift, and 1 J P . C coupling constant values in structural analysis of C-phosphorus-bearing sugars is also reported and discussed.