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A visible-light-induced cascade radical trifluoromethylation/cyclization/dearomatization reaction between isocyanide-containing indoles and CF3Br has been developed to afford trifluoromethylated spiro[indole-3,3-quinoline] and spiro [indole-3,3-pyrrole] derivatives in good yields. The utility of the process is demonstrated by a scale-up experiment. The mechanism was proposed based on the control experiments. The protocol constitutes a novel and efficient route for the synthesis of trifluoromethylated 3-spiroindolenines with advantages of good generality and practical applicability, broad substrate scope, and green energy source.

A concise and efficient method for the construction of fully substituted difluoromethylpyrazoles is achieved by a cyclization reaction between difluoroacetohydrazonoyl bromides and 2-acylacetonitrile or malononitrile. The method features advantages such as mild reaction conditions, broad substrate scope, good product yields, and high regioselectivity.

An efficient [3 + 2] cycloaddition reaction between in situgenerated nitrile imines from hydrazonoyl halides and vinylsulfonium salts is developed. The nitrile imines are demonstrated to be a new class of reaction partner for vinylsulfonium salts to conduct the [3 + 2] cycloaddition reaction. The process provides a concise and efficient method for the construction of pyrazole derivatives under mild reaction conditions with broad substrate scope, good product yields, and high regioselectivity.

As novel difluoromethyl building blocks, difluoromethylated N-acylhydrazones react with allyltrimethylsilanes and the halogen source via a tandem addition/cyclization/halogenation strategy, which produces various difluoromethylpyrazoline compounds in good yields. The method features mild reaction conditions, broad substrate scopes, and a transition metal-free process with easy operation. It also proves that difluoromethylated N-acylhydrazones are useful difluoromethyl building blocks for the construction of difluoromethylated nitrogen heterocycles.

A tandem addition/cyclization reaction between trifluoromethyl N-acylhydrazones and cyanamide is described, which provides a novel and efficient process for the synthesis of polysubstituted 3-trifluoromethyl-1,2,4-triazolines and their derivatives. The method has the advantages of mild reaction conditions, a broad substrate scope, good product yields, and atom economy.

As novel and efficient difluoromethyl building blocks, difluoroacetohydrazonoyl bromides have been synthesized for the first time. The synthetic utility of this reagent for the construction of difluoromethyl organic compounds is demonstrated by their effective regioselective [3 + 2] cycloaddition reactions with ynones, alkynoates, and ynamides. The reactions provide a novel and efficient protocol to access difluoromethyl-substituted pyrazoles in good to excellent yields.

Trifluoromethylated N‐acylhydrazones are used as dipolarophiles to perform 1,3‐dipolar cycloadditions with azomethine ylides to afford trifluoromethylated 1,2,4,5‐tetrasubstituted imidazolidines in good yields under mild conditions. The role switch of the trifluoromethylated N‐acylhydrazones demonstrates that they are versatile trifluoromethyl building blocks for CF3‐containing heterocycles. TrifluoromethylatedN‐acylhydrazonesare used as dipolarophiles to perform 1,3‐dipolar cycloaddition with azomethine ylides to afford trifluoromethylated 1,2,4,5‐tetrasubstituted imidazolidines in good yields under mild conditions.

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.

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. CF2H‐Bubstituted pyrazolines and pyrazoleswere synthesized via[3+2] cycloaddition of difluoroacetohydrazonoyl bromides with α,β‐unsaturated ketones, esters, amides and β‐nitroolefins under mild conditions in good yields.

An efficient cycloaddition reaction of trifluoroacetohydrazonoyl bromides with nitroolefins was developed, which regioselectively produced 3‐trifluoromethyl‐4‐substituted pyrazoles. The reaction has the advantages of mild conditions, good tolerance of functional groups and simple operation. 3‐Trifluoromethyl‐4‐substituted pyrazoleswere synthesized by regioselective [3+2] cycloaddition of in situgenerated trifluoroacetonitrile imines with nitroolefins under mild reaction conditions. This reaction has good scalability and tolerance.