Difluoromethyl nitril oxide (CF₂HCNO): overseen chemical reagent

A novel chemical reagent – difluoromethyl nitrile oxide, CF₂HCNO – was generated in situ for the first time. The synthesis commenced with ethyl difluoroacetate and included only two chemical steps. The difluoromethyl nitrile oxide smoothly participated in [3+2]‐cycloaddition reactions with alkynes and enamines to give CF₂H‐isoxazoles; these products are promising cores for agrochemistry. A representative CHF₂‐isoxazole was incorporated into the known fungicide Fluxapyroxad (BASF), and the synthesized analogue showed higher antifungal activity than the parent fungicide.