Résumé
Building on mechanistic studies, the innate capability of azoles to act as a directing group has been exploited to design an efficient and simple procedure for the hydroamination of N-allenylazoles such as 1-allenyl-1H-pyrazole, 1-allenyl-1H-benzimidazole and 1-allenyl-1H-1,2,3-triazole with secondary amines such as morpholine, piperidine and N-methylcyclohexylamine. The reaction proceeds under mild conditions by copper(I) catalysis yielding the corresponding original linear E-allylic amines, e.g., I with total regio- and stereoselectivity. D. Functional Theory (DFT) calcns. offer a mechanistic explanation of the significantly higher reactivity of N-allenyl-(1,2)-azoles compared to their 1,3-analogs as a result of the reaction-enhancing coordination of the pyridine-like nitrogen to the copper center.