Comparative Reactivity of Different Types of Stable Cyclic and Acyclic Mono- and Diamino Carbenes with Simple Organic Substrates
作者:David Martin、Yves Canac、Vincent Lavallo、Guy Bertrand
DOI:10.1021/ja412981x
日期:2014.4.2
A series of stable carbenes, featuring a broad range of electronic properties, were reacted with simple organic substrates. The N,N-dimesityl imidazolylidene (NHC) does not react with isocyanides, whereas anti-Bredt di(amino)carbene (pyr-NHC), cyclic (alkyl)(amino)carbene (CAAC), acyclic di(amino)carbene (ADAC), and acyclic (alkyl)(amino)carbene (AAAC) give rise to the corresponding ketenimines. NHCs
一系列具有广泛电子特性的稳定卡宾与简单的有机底物反应。N,N-二甲基咪唑亚基 (NHC) 不与异氰化物反应,而抗 Bredt 二(氨基)卡宾(pyr-NHC)、环状(烷基)(氨基)卡宾(CAAC)、无环二(氨基)卡宾( ADAC)和无环(烷基)(氨基)卡宾(AAAC)产生相应的烯酮亚胺。已知 NHC 可促进安息香缩合,我们发现 CAAC、pyr-NHC 和 ADAC 与苯甲醛反应生成 Breslow 中间体的酮互变异构体,而 AAAC 首先生成相应的环氧化物,最终生成 Breslow 中间体,其可以隔离。向后者添加过量的苯甲醛不会产生安息香,而是产生稳定的 1,3-二氧戊环。根据卡宾的电子性质,以丙烯酸甲酯为底物也可得到不同的产品。讨论了卡宾亲电性对反应结果的关键作用。