Dipole moments and structure of some cyclic phosphonic esters

Abstract

1. We were the first to determine the group dipole moment of the 4,4,5,5-tetramethyl-2-oxo-1,3,2-dioxaphospholane ring, which is directed toward the exocyclic bond of phosphorus at an angle of 81°. 2. The 5,5-dimethyl-2-phenyl-2-oxo-and 2-p-chlorophenyl-2-oxo-1,3,2-dioxaphosphorinanes exist in solutions as a conformational equilibrium of the forms with an equatorial and axial P=O group, with predominance of the latter. © 1979 Plenum Publishing Corporation.