Abstract A protocol for the N-bromosuccinimide (NBS)-and trichloroisocyanuric acid (TCCA)- mediated cleavage of the C [BOND] C bond of isoxazoline N-oxides, fused with a cyclohexene ring, leading to the production of a long-chain diketo-halo-nitrile skeleton is described. The conversion occurs via the formation of a nitric oxide intermediate.