Heptafluoroisopropyl diazomethane (i-C3F7CHN2): in situ generation and synthesis of pyrazoles

A novel chemical reagent - heptafluoroisopropyl diazomethane (i-C3F7CHN2) - has been generated in situ in aqueous media. It readily reacts with electron-deficient alkynes towards polyfluorinated pyrazoles that are important in agrochemistry.