C–H Amination Mediated by Cobalt Organoazide Adducts and the Corresponding Cobalt Nitrenoid Intermediates
作者:Yunjung Baek、Anuvab Das、Shao-Liang Zheng、Joseph H. Reibenspies、David C. Powers、Theodore A. Betley
DOI:10.1021/jacs.0c04252
日期:2020.6.24
3-dipolar cycloaddition as well as C-H amination to furnish 1,2,3-dihydrotriazole and substituted pyrrolidine products, respectively. For the C-H amination, we observe that the temperature required for azide activation varies depending on the presence of weak C-H bonds, suggesting that the alkyl azide adducts serve as viable species for C-H amination when the C-H bonds are (1) proximal to the azide
用化学计量的 1-叠氮基-4-(叔丁基)苯 N3(C6H4-p) 处理 (ArL)CoBr (ArL = 5-mesityl-1,9-(2,4,6-Ph3C6H2)dipyrrin) -tBu) 提供了相应的四坐标有机叠氮化物结合的络合物 (ArL)CoBr(N3(C6H4-p-tBu))。复合物的光谱和结构表征表明有机叠氮化物的氧化还原无害连接。在室温下观察到二氮 (N2) 的缓慢排出,通过 [3+2] 环化提供配体官能化产物,该产物可由高价氮烯中间体如 CoIII 亚胺基 (ArL)CoBr(·N (C6H4-p-tBu)) 或 CoIV 亚氨基 (ArL)CoBr(N(C6H4-p-tBu)) 络合物。所提出的中间体的存在及其作为氮烯基团转移试剂的可行性得到了分子间 CH 胺化和氮丙啶化反应的支持。与 (ArL)CoBr(N3(C6H4-p-tBu)) 不同,一系列烷基叠氮化物结合的