Kinetically deduced existence of C=O·····C close contacts. Pericyclic rearrangement of 1,2-diacetyl-1,2-dihydro-3H-indazol-3-one

Article abstract of DOI:10.1016/0040-4039(94)02440-M

First-order kinetics of the title rearrangement to 3-acetoxy-1-acetylindazole (2a), complete exchange of O-acyl groups in cross-experiments, insensitivity to change in reaction medium, lack of electronic substituent effects and activation parameters are considered as evidence in favour of a pericyclic mechanism through C=O·····C close contacts.