Initial experiments surveyed common hydrogen transfer catalysts, in both the presence and absence of a hydrogen acceptor (crotonitrile)No pyrazole formation was observed in
the presence of [Cp*IrCl2]2, Milstein’s catalyst, or RuCl2(PPh3)3 (Table 1, entries 1−3). [Ru3(CO)12] and Xantphos in tert-amyl alcohol, which was utilized by Beller and co-workers for vicinal diol dehydrogenation