Spatial structure of phosphorus-containing heterocycles. 31. 2-dialkylamino-l,3,2-dioxaphosphorinanes with four-coordinated phosphorus

Abstract

1. For 2-dialkylamino-2-thiono-1,3,2-dioxaphosphorinanes, the preferred conformation is the cross with the axial position of the thiophosphoryl group. Cis-2-diethylamino-2-thiono-4-methyl-1,3,2-dioxaphosphorinane has an analogous structure with equatorial orientation of the 4-methyl. The trans isomer exists in the form of a three-component equilibrium of two conformations of the cross and a flexible form. In the 5-spirooxethane derivatives, the difference between the energies of the two cross conformations is reduced to 0.67 kcal/mole. 2. An increase has been found in the longitudinal component of anisotropy of P=S bond polarizability in 2-dialkylamino-2-thiono-l,3,2-dioxaphosphorinanes γ(P=S) 4.08 Å3 in comparison with the corresponding thiophosphates γ(P=S) 3.36 Å3. © 1983 Plenum Publishing Corporation.