Volk Julia, Heinz Myron, Guthardt Robin, Yadav Suman, Bruhn Clemens, Holthausen Max C, Siemeling Ulrich
Institute of Chemistry, University of Kassel, Heinrich-Plett-Straße 40, 34132, Kassel, Germany.
Present address: Chemistry Department, Laboratory of organic reactivity and catalysis, University of Namur, Rue de Bruxelles 61, 5000, Namur, Belgium.
Chemistry. 2024 Dec 10;30(69):e202403028. doi: 10.1002/chem.202403028. Epub 2024 Oct 29.
The recently described crystalline cyclic (alkyl)(amino)carbene with a 1,1'-ferrocenylene (fc) backbone fc(CPh-C-NMes) (A, Mes=mesityl) is highly reactive due to its particularly pronounced ambiphilicity and is thermally not stable in solution due to an intramolecular insertion of the divalent carbon atom into a methyl C-H bond of the Mes substituent. The closely related congener fc(CPh-C-N-p-CH-tBu) (1) cannot undergo such an insertion reaction. Nevertheless, 1 is too short-lived for isolation due to a rapid 1,2-shift of a phenyl group, furnishing the isomeric cyclic enamine fc[C(Ph)=C(Ph)-N-p-CH-tBu] (1') in a specific decomposition process unprecedented for CAACs. Trapping of 1 was possible with carbon monoxide, elemental selenium and with [CuBr(SMe)], respectively affording the aminoketene 1=C=O, the selenoamide 1=Se and the homoleptic Cu complex [Cu(1)][CuBr]. 1 is an even stronger ambiphile than A according to NMR spectroscopic data. Similar to A, 1 does not react with H, because the experimentally observed intramolecular process is kinetically more favourable according to DFT results.
最近报道的具有1,1'-二茂铁撑（fc）主链fc（CPh - C - NMes）（A，Mes = 均三甲苯基）的结晶性环状（烷基）（氨基）卡宾，由于其特别显著的双亲性而具有高反应活性，并且由于二价碳原子分子内插入到Mes取代基的甲基C - H键中，在溶液中热不稳定。密切相关的同系物fc（CPh - C - N - p - CH - tBu）（1）不能发生这种插入反应。然而，由于苯基的快速1,2 - 迁移，1寿命太短而无法分离，在一种对于环状（烷基）（氨基）卡宾前所未有的特定分解过程中生成异构体环状烯胺fc[C(Ph)=C(Ph)-N - p - CH - tBu]（1'）。分别用一氧化碳、元素硒和[CuBr(SMe)]捕获1，得到氨基乙烯酮1 = C = O、硒代酰胺1 = Se和均配型铜配合物[Cu(1)][CuBr]。根据核磁共振光谱数据，1是比A更强的双亲试剂。与A类似，1不与H反应，因为根据密度泛函理论结果，实验观察到的分子内过程在动力学上更有利。
