Brønsted acid-catalyzed cascade cyclization: an efficient strategy for divergent synthesis of cyclohepta[b]indole derivatives. Issue 19 (22nd September 2022)

• Record Type: Journal Article
• Authors: Chen, Shaomin; Chen, Zhiyan; Zhang, Tianjian; Zhao, Bo; You, Bo; Li, Minghao; Gu, Yanlong
• Is Part Of: Green chemistry. Volume 24:Issue 19(2022)
• Page Start: 7376
• Page End: 7381
• Publication Date: 2022-09-22
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/d2gc02072f
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : An efficient acid-catalyzed three-component cascade strategy by employing 3, 3′-bis(indolyl)methanes (BIMs) as masked 1, 4-nucleophiles was established for synthesizing cyclohepta[ b ]indoles under mild and eco-friendly conditions. Abstract : An efficient acid-catalyzed three-component cascade strategy was established on the basis of a crucial conversion of BIMs to vinylindoles to synthesize a privileged scaffold, phenyl-substituted dihydrocyclohepta[ b ]indole carboxylate. The vinylindole intermediates worked as 1, 4-bisnucleophiles and could be trapped by atropaldehyde acetals to construct diphenyl-substituted dihydrocyclohepta[ b ]indoles. A [5 + 2] cyclization of 2-aryl-3, 4-dihydropyrans with 2, 3-unsubstituted indoles was also established, which provided another route to access tetrahydrocyclohepta[ b ]indoles. Readily available materials, inexpensive metal-free catalysts, eco-friendly solvents and divergent synthesis ensured these methods are practically attractive.