Transition metal imide-mediated C–N bond formation is a powerful strategy for the introduction of nitrogen into organic compounds. We have discovered that the reaction of N-mesityl(β-diketiminato)iron imide complex ^tBuLFeNMes (^tBuL = 3,5-bis(2,6-diisopropylphenylimino)-2,2,6,6-tetramethylheptyl and Mes = 2,4,6-trimethylphenyl) with a terminal alkyne substrate gives a β-alkynyl enamine product by a novel alkyne carboamination process. Stoichiometric experiments revealed a catalyst deactivation pathway involving generation of the acetylide complex, ^tBuLFeCCPh, and mesityl amine (MesNH₂) from the acetylene complex, ^tBuLFe(HCCPh), and mesityl azide (MesN₃). This reactivity is suppressed in the presence of coordinating additive 4-tert-butylpyridine (^tBuPy), likely through formation of the four-coordinate complex ^tBuLFe(HCCPh)(^tBuPy). These insights were instrumental in identifying reaction conditions that allow for turnover of the iron catalyst.

中文翻译：

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通过可分离的亚铁配合物进行铁催化的炔烃碳胺化

过渡金属酰亚胺介导的 C-N 键形成是将氮引入有机化合物的有效策略。我们发现N -mesityl(β-diketiminato)iron imide 络合物^{t Bu} LFeNMes ( ^{t Bu} L = 3,5-bis(2,6-diisopropylphenylimino)-2,2,6,6-tetramethylheptyl 和 Mes = 2,4,6-三甲基苯基）与末端炔烃底物通过新型炔烃碳胺化过程产生 β-炔基烯胺产物。化学计量的实验揭示催化剂失活途径涉及产生乙炔化复杂的，^吨卜LFeCCPh，和三甲苯基胺（MesNH ₂）从乙炔复杂，^吨卜LFe(HCCPh) 和甲基叠氮化物 (MesN ₃ )。这种反应性在配位添加剂 4-叔丁基吡啶 ( ^t BuPy)的存在下受到抑制，可能是通过形成四配位配合物^{t Bu} LFe(HCCPh)( ^t BuPy)。这些见解有助于确定允许铁催化剂周转的反应条件。