A facile palladium-catalyzed route to 2, 5, 7-trisubstituted indoles. Issue 49 (9th December 2015)

• Record Type: Journal Article
• Authors: Cacchi, Sandro; Fabrizi, Giancarlo; Goggiamani, Antonella; Iazzetti, Antonia; Verdiglione, Rosanna
• Is Part Of: Tetrahedron. Volume 71:Issue 49(2015)
• Page Start: 9346
• Page End: 9356
• Publication Date: 2015-12-09
• Subjects: Polysubstituted indoles -- One-pot reactions -- Palladium -- Cross-coupling; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2015.10.002
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: A facile and general approach to the synthesis of 2, 5, 7-trisubstituted indoles from readily available 2-bromo-6-iodo-4-substituted and 2-bromo-4-chloro-6-iodoanilines is reported. The assembly of the indole rings is accomplished via a one-pot Sonogashira cross-coupling with terminal alkynes followed by a palladium-catalyzed cyclization step. The functionalization at C7 and at C5 (with indoles bearing a chloro substituent at C5) is carried out by alkynylations, Suzuki–Miyaura cross-couplings, and Buchwald-Hartwig C–N bond forming reactions. One-pot protocols for the synthesis of 2, 5, 7-trisubstituted indoles from 2-aryl-7-bromo-5-chloroindoles as well as from 2-bromo-4-chloro-6-iodoaniline are also described. Graphical abstract: