A Theoretical Study on Applying Conformational Analysis of 2-Halo-2-Oxo-1,3,2-Dioxaphosphorinanes

The quantum-chemical calculations on the conformational properties of 2-flouro-2-oxo-1,3,2-dioxaphosphorinane (1), 2-choloro-2-oxo-1,3,2-dioxaphosphorinane (2) and 2-bromo-2-oxo-1,3,2-dioxaphosphorinane (3) have been investigated by means of ab initio molecular orbital (hf/6-311+g**) and hybrid density functional theory (b3lyp/6-311+g**) based methods and natural bond orbital (nbo) interpretation in solid state was performed. geometrical analysis supports clearly the participation of hyperconjugative endo-anomeric (lpo→σ*p-x) effect in the stabilization of axial series of compounds and the participation of exo-anomeric (lpx→σ*p-o) effect in the stabilization of the equatorial phosphinanes in chair conformations. the stereoelectronic effects associated with bonding-anticoding delocalization electron are more significant for the explanation of the conformational behavior of compounds 1-3 than the dipole-dipole interaction effects.