Next, we investigated various analogs of disubstituted ethane as co-reactants with 4-BrPyCN during the course of ROI (Table ). As reported, dibromoethane was originally employed to impart a cyclopropyl ring alpha to the pyrazolyl nitrogen within 4-BrPyCN, leading to the anticipated C4-Bromopyrazolyl cyclopropane carbonitrile (Fig. ). However, in the present study, upon screening ROI with various disubstituted ethane, we observed the formation of Py-N-ene only with homo/hetero substituted dihaloethane (entry 1, 2, and 3 in Table ). Interestingly, we did not observe Py-N-ene in the reactions with monohalosubstituted (entry 4 in Table ) or no halogen substituted ethane as co-reactant (entry 5 and 6 in Table ). These observations suggest a significant role of good leaving groups (i.e., halides) on both ends of the ethyl backbone (as co-reactant) for the formation of Py-N-ene.