Orthogonal Synthesis of Densely Functionalized Pyrroles and Thiophenes from the Reactions of Imidazo[1,5-<i>a</i>]pyridine Carbene-Derived Zwitterions with Electron-Deficient Alkynes
作者:Ying Cheng、Jiang-Hua Peng、Jia-Qi Li
DOI:10.1021/jo100225r
日期:2010.4.2
1-Thiocarbamoyl imidazo[1,5-a]pyridinium inner salts, which were obtained readily from the addition of C,N-substituted heterocyclic carbenes imidazo[1,5-a]pyridine-1-ylidenes to isothiocyanates, are powerful ambident nucleophilic zwitterions. They acted as nitrogen nucleophiles toward ethyl propiolate to produce polyfunctionalized pyrrole derivatives in high yields. When treated with dimethyl acetylenedicarboxylate
1-硫代氨基甲酰基咪唑并[1,5- a ]吡啶鎓内盐很容易获得,该盐是通过将C,N-取代的杂环卡宾咪唑并[1,5 - a ]吡啶-1-亚胺添加到异硫氰酸酯中而得到的,具有很强的环境亲核性。两性离子。它们充当了对丙酸乙酯的氮亲核试剂,以高收率生产了多官能化的吡咯衍生物。当用乙炔基二羧酸二甲酯处理时,它们仅作为硫亲核试剂,以极好的收率提供完全取代的噻吩。这项工作提供了多官能化的吡咯和噻吩的高效正交合成,而其他化学方法不易获得。