Vinylidenediamine intermediate was not found in amination reactions of Ni-propyl-p- substituted-phenylketenimines with n-BuNH2, but it was found in amination reactions of Np- substituted-phenylphenylketenimines with n-BuNH2 by low-temperature 1H NMR spectrometer, indicating that the rate-determining step is changed from the first step (CN addition) to the second step (tautomerization) when N-substituent of the ketenimines is ...
