College of Chemistry, Beijing Normal University, Beijing 100875, China.
J Org Chem. 2010 Apr 2;75(7):2382-8. doi: 10.1021/jo100225r.
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, they behaved exclusively as sulfur nucleophiles to afford fully substituted thiophenes in excellent yields. This work provides highly efficient orthogonal synthesis of polyfunctionalized pyrroles and thiophenes that were not easily obtained by other chemical means.
1-硫代碳酰基咪唑并[1,5-a]吡啶鎓内盐很容易通过 C,N-取代杂环卡宾咪唑并[1,5-a]吡啶-1-亚基与异硫氰酸酯加成得到，是一种强两性亲核两性离子。它们作为氮亲核试剂与丙炔酸乙酯反应，以高产率得到多官能化吡咯衍生物。当与二甲基丙炔二羧酸酯反应时，它们仅作为硫亲核试剂，以优异的收率得到完全取代的噻吩。这项工作提供了高效的多官能化吡咯和噻吩的正交合成方法，这些化合物不容易通过其他化学方法获得。
