Comment on "trans-1,2-Disiloxybenzocyclobutene, an adequate partner for the auto-oxidation: EPR/spin trapping and theoretical studies" by J. Drujon et al., Phys. Chem. Chem. Phys., 2014, 16, 7513.

Despite the claim of the contrary, (i) the facile formation of a ring-opened cyclic peroxide from reaction of a 1,2-disubstituted benzocyclobutene with molecular oxygen has been reported before, and (ii) the analysis of the mechanistic steps of this process is incomplete, as only the symmetry-allowed conrotatory ring-opening of the benzocyclobutene has been considered. The probable involvement of biradical intermediates/biradicaloid transition states in a formally symmetry-forbidden reaction sequence has not been taken into account.