The structure effects on the rearrangement and alkaline hydrolysis reactions for title compounds I (R1, R2 = MeO, MeO; MeO, Et; Et, Et) are investigated by MM and MNDO methods. The results indicate that the activation energies of the rearrangement reactions increase with the increasing no. of the C-P bonds in the substrates, that is consistant with the experimental results. On the contrary the activation energies for the alkaline hydrolysis reaction are opposite to the experimental results, which can be explained by the difference of the solvent effects between the substrates and the transition states.

Key words: PHOSPHONIC ACID ESTER, QUANTUM CHEMISTRY, MOLECULAR MECHANICS, REARRANGEMENT REACTION, HYROLYSIS, STRUCTURAL EFFECT