Radical Cascade Cyclization of Unsaturated Aldehyde Hydrazones for the Synthesis of Trifluoromethylated Tetrahydropyridazine and Dihydropyrazole Skeletons

Herein, we report a cascade cyclization reaction mediated by trifluoromethyl radicals using N -allyl and homoallyl aldehyde hydrazones and CF 3 SO 2 Na as the starting materials. This approach enables the efficient synthesis of 30 trifluoromethylated tetrahydropyridazine and dihydropyrazole derivatives in moderate yields, with the highest yield reaching 81%. Importantly, this process does not require metal catalysts, which not only makes the process more cost-effective but also enhances its overall appeal and practicality in organic synthesis.