A Facile Synthesis of CF₃-Substituted Pyrazolidines and Pyrazolines

A density functional theory study of the stereoselectivity of Cu(OTf)2‐catalyzed [3+2] cycloaddition of trifluoromethylated N‐acylhydrazones and isoprene: A concerted asynchronous mechanism

“…In addition, P1, P3, P5, and P7 can be classified into the syn structures mentioned in the previous experimental study, while the remaining P2, P4, P6, and P8 can be regarded as the anti structures. [ 33 ] However, the experimental study reveals that the syn form is the major product when using the Cu(OTf) 2 as catalyst under room temperature, with a ratio of 72:28. To clarify such diastereoselectivity, we need to further investigate the reaction processes in detail.…”

“…[ 29–32 ] However, investigations concerning the synthesis of CF 3 ‐substituted pyrazolidines and pyrazolines are rather limited. [ 33–39 ] Therefore, methods that can synthesize CF 3 ‐substituted pyrazolidines and pyrazolines efficiently have been widely explored owing to their potential applications in the fields of biology and materials.…”

“…Recently, Hu et al systematically investigated the synthesis of CF 3 ‐substituted pyrazolidines. [ 33 ] They conducted the [3+2] reactions of trifluoromethylated N ‐acylhydrazones and isoprene using different Lewis acids as catalysts. Based on their results, they found that using Cu(OTf) 2 as catalyst can generate trifluoromethylated pyrazolidines in both good yield and diastereoselectivity with the reaction mechanism shown in Figure 1.…”

“…Mechanism of Cu(OTf) 2 ‐catalyzed [3+2] cycloaddition of trifluoromethylated N ‐acylhydrazones and isoprene proposed by previous experimental study 33 …”

Synthesis of 3-Trifluoromethyl-1,2,4-triazolines and 1,2,4-Triazoles via Tandem Addition/Cyclization of Trifluoromethyl N-Acylhydrazones with Cyanamide

“…Although amino-1,2,4-triazole scaffolds play important roles in agrochemical and medicinal communities, research studies about the synthesis of trifluoromethylated amino-1,2,4-triazoles have not been reported until now. In our group, we have used trifluoromethylated N -acylhydrazones as formal 1,3-dipoles to react with a series of electron-deficient olefins via [3 + 2] cycloaddition to obtain trifluoromethyl-substituted nitrogen heterocycles such as pyrazoles and pyrazolidines . In addition, trifluoromethyl N -acylhydrazones can also be used as dipolarophiles to react with azomethineylide to produce trifluoromethyl-substituted imidazolidines .…”