Halonium Ion Mediated Synthesis of 2‑Halomethylene-3-oxoketoxime Derivatives from Isoxazoline N‑Oxides

A protocol for the N-bromosuccinimide (NBS)- and trichloroisocyanuric acid (TCCA)-mediated synthesis of novel 2-halomethylene-3-oxoketoximes via one-pot halogenation/oxidation of isoxazoline N-oxide derivatives is described here. The keto functionality of 3-ketoximes was selectively reduced by lithiumaluminum hydride to synthesize an unprecedented type of Baylis–Hillman oxime, which underwent N–O coupling to produce new isoxazoline N-oxide derivative.