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.

An efficient and novel photoinduced trifluoromethylation employing CF 3 Br as a trifluoromethyl source is described. With commercially accessible fac -Ir (III) (ppy) 3 as the catalyst, radical trifluoromethylation between O -silyl enol ether and CF 3 Br occurs successfully. This method provides various α-CF 3 -substituted ketones with a broad substrate scope in good yields under mild reaction conditions.

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.