Is 2-oxabicyclobutane formed during the reaction of peroxyacids with cyclopropene? A high-level ab initio study

High-level quantum chemical studies have been carried out to explain the unusual course of the reaction of peroxyacids with cyclopropene. The results of calculations at the CASSCF and UQCISD levels of theory suggest that 2-oxabicyclobutane is not formed during this reaction. An unsymmetrical transition state is formed during this reaction and is followed by the formation of a biradical intermediate which finally yields acroleine after the fast proton transfer step.