A DFT study of the Boulton-Katritzky rearrangement of (5R)-4-nitrosobenz[c]isoxazole and its anion: pseudopericyclic reactions with aromatic transition states.

The nature of the Boulton-Katritzky rearrangement of (5R)-4-nitrosobenz[c]isoxazole and its anion was studied employing three methodologies: calculation of magnetic properties (magnetic susceptibility, magnetic susceptibility anisotropy, and the nucleus-independent chemical shifts), the natural bonding orbital analysis, and the ACID (anisotropy of the current-induced density) method. The deep analysis of the results indicates a pseudopericyclic character for these reactions despite the aromaticity of the transition states.