One-Pot Synthesis of CF3-Substituted Pyrazolines/Pyrazoles from Electron-Deficient Alkenes/Alkynes and CF3CHN2 Generated in situ: Optimized Synthesis of Tris(trifluoromethyl) pyrazole

The [3+2] cycloaddition of CF3CHN2, generated in situ, with electron-deficient alkenes/alkynes affords CF3-substituted pyrazolines/pyrazoles in quantitative yields. The one-pot three-component reaction between CF3CH2NH2HCl, NaNO2, and the substrate proceeds at room temperature in dichloromethane/water.