Bisimide-lactamimide ring contraction in six-membered bisimides: a theoretical study

The bisimide-lactamimide ring contraction reaction of six-membered bisimide s has been modeled at the B3PW91/6-31 + G(d,p)//HF/3-21G level of theory us ing the isodensity polarized continuum model to take into account the solve nt effect. Basically, the results of molecular modeling support the validit y of the proposed mechanism. However, the calculations suggest that the fin al reaction step involves the direct oxidation of dianions by molecular oxy gen, instead of oxidation of the hydroaromatic intermediate as proposed pre viously. The reactivity difference between N-alkyl and N-phenyl bisimides i n the ring contraction reaction has been explained. Copyright (C) 2001 John Wiley & Sons, Ltd.