Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, 710054 (P.R. China).
State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin 300071 (P.R. China).
Angew Chem Int Ed Engl. 2015 Dec 1;54(49):14915-9. doi: 10.1002/anie.201507844. Epub 2015 Oct 12.
Cyclic (amino)(aryl)carbenes (CAArCs) result from the replacement of the alkyl substituent of cyclic (alkyl)(amino) carbenes (CAACs) by an aryl group. This structural modification leads to enhanced electrophilicity of the carbene center with retention of the high nucleophilicity of CAACs, and therefore CAArCs feature a small singlet-triplet gap. The isoindolium precursors are readily prepared in good yields, and deprotonation at low temperature, in the presence of [RhCl(cod)]2 and [(Me2S)AuCl] lead to air-stable rhodium and gold CAArC-supported complexes, respectively. The rhodium complexes promote the [3+2] cycloaddition of diphenylcyclopropenone with ethyl phenylpropiolate, and induce the addition of 2-vinylpyridine to alkenes by CH activation. The gold complexes allow for the catalytic three-component preparation of 1,2-dihydroquinolines from aniline and phenyl acetylene. These preliminary results illustrate the potential of CAArC ligands in transition-metal catalysis.
环状（氨基）（芳基）碳烯（CAArCs）是通过将环状（烷基）（氨基）碳烯（CAACs）中的烷基取代基替换为芳基而得到的。这种结构修饰导致卡宾中心的亲电性增强，同时保留 CAACs 的高亲核性，因此 CAArCs 具有较小的单重态-三重态能隙。异吲哚啉前体可高产率制备，在[RhCl(cod)]2 和[(Me2S)AuCl]的存在下低温脱质子，分别得到稳定的空气的铑和金 CAArC 负载配合物。铑配合物促进二苯基环丙烯酮与乙基苯丙炔酸酯的[3+2]环加成，通过 CH 活化诱导 2-乙烯基吡啶加成到烯烃上。金配合物允许从苯胺和苯乙炔催化三组分制备 1,2-二氢喹啉。这些初步结果说明了 CAArC 配体在过渡金属催化中的潜力。
