Theoretical study of 1,3-dipolar cycloaddition reactions of diphenylnitrilimine with highly fluorinated dipolarophiles

The 1,3-dipolar cycloaddition reactions of diphenylnitrilimine with various fluorinated dipolarophiles have been investigated with the use of ab initi o molecular orbital calculations to elucidate the mechanistic aspects of th e reaction based on the kinetic and frontier molecular orbital (FMO) theore tical points of views. Structure optimizations were performed with the RHF/ 3-21G, RHF/6-31G* and density functional B3LYP/6-31G* methods. The transiti on state geometries and energy barriers depend on the level of calculations . The results provide a good prediction of the relative rates observed expe rimentally. Regioselectivity of the products of the reaction is also predic ted reliably by the calculations. The perturbative analysis shows a strong HOMO (dipole)-LUMO (dipolarophile) interaction as the principal reason for the reactivity in these 1,3-dipolar cycloaddition reactions. (C) 2001 Elsev ier Science B.V. All rights reserved.