Synthesis of 3-Trifluoromethyl-1,4-dihydropyridazines by the PTSA-Catalyzed Reaction of α,β-Unsaturated Aldehydes with (E)-1-Phenyl-2-(2,2,2-trifluoroethylidene) - Xie, Haibo; Zhu, Jiangtao; Chen, Zixian; Li, Shan; Wu, Yongming (Synlett, 2012)