Difluoroacetohydrazonoyl bromides, which are stable in air at room temperature, are demonstrated to be good difluoromethyl building blocks for construction of CF2H‐substituted pyrazoline and pyrazole compounds via [3+2] cycloaddition with electron‐deficient olefins under mild conditions. A series of CF2H‐substituted pyrazolines and pyrazoles were obtained in good yields. The method has the advantages of mild reaction conditions, good regioselectivity, broad substrate scopes and easy operation.

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Efficient visible-light-induced radical cascade trifluoromethylation/cyclization of inactivated alkenes with CF3Br, which is a nonhygroscopic, noncorrosive, cheap and industrially abundant chemical, was developed in this work, producing trifluoromethyl polycyclic quinazolinones, benzimidazoles and indoles under mild reaction conditions. The method features wide functional group compatibility and a broad substrate scope, offering a facile strategy to pharmaceutically produce valuable CF3-containing polycyclic aza-heterocycles.

A visible-light-induced four-component Ritter-type reaction was developed for the synthesis of β-trifluoromethyl imides from CF3Br, alkenes, carboxylic acids, and nitriles. This protocol features mild reaction conditions, a broad substrate scope, and excellent functional group compatibility. Furthermore, this method has been proven to be suitable for the late-stage diversification of drug molecules. A mechanism involving a Ritter-type reaction and Mumm rearrangement was proposed on the basis of the control experiments.

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