One-Pot Assembly of 2-Trifluoromethyl Benzothiazole and Benzoselenazole via Copper-Mediated Three-Component Cascade Reaction.

A domino one-pot synthesis of 2-(trifluoromethyl) benzothiazole via copper-mediated three-component cascade reaction starting from the easily accessible starting materials such as o-iodoanilines, methyl trifluoropyruvate, and elemental sulfur is reported. The present strategy displayed a comprehensive substrate scope and good functional group tolerance and enabled access to a variety of substituted 2-(trifluoromethyl) benzothiazoles. A 2-(trifluoromethyl) benzoselenazole has also been synthesized utilizing this reaction methodology.

Copper-Catalyzed Synthesis of 5-Aryl-6-(Trifluoromethyl)-2,3-Dihydropyrazolo[1,2-a]Pyrazol-1(5H)-One.

An efficient protocol for the synthesis of 5-aryl-6-(trifluoromethyl)-2,3-dihydropyrazolo[1,2-a]pyrazol-1(5H)-one derivatives through a copper-catalyzed [3+2]-cycloaddition of azomethine imines with 3,3,3-trifluoropropyne (generated in situ from dehydrobromination of 2-bromo-3,3,3-trifluoropropene under base conditions) is developed. The advantages of this transformation are the broad substrate scope and the good functional group compatibility. The subsequent oxidation and nucleophilic substitution/aromatization provide a new approach to 4-trifluoromethylated pyrazol-1-yl propanoic acids.

Perfluorocarboxylic Anhydrides Triggered Cyclization: Access to 4-Perfluoroalkylpyridines.

A double nucleophilic addition-cyclization-elimination cascade is developed, that allows various 2,6-diaryl-4-perfluoroalkylpyridines to be synthesized in one step from easily available enamides and perfluorocarboxylic anhydrides. The procedure is also operationally simple and scalable and provides access to the facial construction of 4-fluoroalkylpyridines, which are of great interest in medicinal chemistry.

Synthesis of 3-(tri/difluoromethyl)-1H-1,2,4-triazol-5(4H)-ones via the cyclization of hydrazinecarboxamides with tri/difluoroacetic anhydride.

An efficient method for the synthesis of structurally diverse 4-aryl-3-(tri/difluoromethyl)-1H-1,2,4-triazol-5(4H)-ones through the cyclization of hydrazinecarboxamides with tri/difluoroacetic anhydride is presented. The method is simple and environmentally benign, providing tri/difluoromethylated 1,2,4-triazol-5(4H)-ones in moderate-to-good yields. A mechanism is proposed to proceed via a tandem reaction of tri/difluoroacetylation, nucleophilic addition and water elimination. Some of these compounds exhibit promising insecticidal activities.