Intermolecular Triazene Alkene Cycloaddition via Lewis Base Catalysis: Access to Diverse Trifluoromethylated
Shiyong Peng1,2, Huijuan Zhu1,3, Haiyun Wu4
1Hainan Branch of the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &, Peking Union Medical College, Haikou, Hainan, 570311, China.
Abstract:
A novel approach to chemoselective synthesis of biologically important CF3 -subsituted pyrazolines was developed via a Lewis base catalyzed intermolecular triazene cycloaddition reaction of an array of terminal/internal alkenes with CF3 CHN2 . This strategy features a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene, high yields (up to 95 %), wide substrate scope and excellent functional group tolerance (54 examples). Importantly, we preformed scaffold diversification of a panel of known pharmaceuticals, natural products, and bioactive heterocycles to generate the corresponding pyrazoline derivatives with potential broad bioactivities for further development.
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