Fe-Catalyzed Novel Domino Isomerization/Cyclodehydration of Substituted 2‑[(Indoline-3-ylidene)(methyl)]benzaldehyde Derivatives: An Efficient Approach toward Benzo[b]carbazole Derivatives

A new and efficient protocol to synthesize substituted benzo­[b]­carbazole derivatives has been demonstrated involving iron-catalyzed domino isomerization/cyclodehydration sequences from substituted 2-[(indoline-3-ylidene)­(methyl)]­benzaldehyde derivatives. The substrates could be easily made via Pd-catalyzed domino Heck–Suzuki coupling from 2-bromo-N-propargylanilide derivatives in high yields. Notably, the generality and efficiency of this two-stage domino strategy was further exemplified by the synthesis of a polycyclic benzofuran derivative.

本研究开发并验证了一种合成取代苯并[b]咔唑（benzo[b]carbazole）衍生物的全新高效方案：以取代的2-[(吲哚啉-3-亚基)(甲基)]苯甲醛衍生物为底物，通过铁催化的多米诺异构化/环脱水串联反应实现。该类底物可通过2-溴-N-炔丙基苯胺衍生物经钯催化的多米诺Heck-Suzuki偶联反应便捷制备，且收率优异。值得注意的是，这一两阶段多米诺合成策略的通用性与高效性，可通过多环苯并呋喃衍生物的合成进一步得到例证。