[4+2] Annulation of 3-(2, 2-diethoxyethyl)-1, 3-dicarbonyl compounds with indoles catalyzed by Brønsted acid ionic liquid for the synthesis of carbazoles. Issue 48 (28th November 2018)

• Record Type: Journal Article
• Authors: Du, Yuying; Xue, Wenyu; Gao, Ruoxuan; Gu, Yanlong; Han, Limin
• Is Part Of: Tetrahedron letters. Volume 59:Issue 48(2018)
• Page Start: 4221
• Page End: 4225
• Publication Date: 2018-11-28
• Subjects: [4+2] Annulation -- Carbazoles -- Brønsted acid ionic liquid -- Acid catalysis; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2018.10.029
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Various carbazoles were synthesized via [4+2] annulation. 1, 3-Dicarbonyl compounds and indoles afforded excellent yields of carbazoles. A Brønsted acid ionic liquid was proven to be effective catalyst for this reaction. The ionic liquid catalyst can be recycled at least three times. Abstract: Various carbazoles were synthesized via [4+2] annulation of 3-(2, 2-diethoxyethyl)-1, 3-dicarbonyl compounds with indoles. A Brønsted acid ionic liquid, [BPy]HSO4, was proven to be effective catalyst for this reaction. The ionic liquid catalyst can be recycled three times without significant loss of its catalytic activity.