From Benzofurans to Indoles: Palladium‐Catalyzed Reductive Ring‐Opening and Closure via β‐Phenoxide Elimination. Issue 1 (26th November 2018)

• Record Type: Journal Article
• Authors: Perego, Luca A.; Wagschal, Simon; Grüber, Raymond; Fleurat‐Lessard, Paul; El Kaïm, Laurent; Grimaud, Laurence
• Is Part Of: Advanced synthesis & catalysis. Volume 361:Issue 1(2019)
• Page Start: 151
• Page End: 159
• Publication Date: 2018-11-26
• Subjects: Heck reaction -- palladium -- benzofuran -- ring opening -- indole; Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201801225
• Languages: English
• ISSNs: 1615-4150

Abstract

Abstract: Benzofurans can undergo ring‐opening by a palladium‐catalyzed process resulting in C−O bond breaking. Benzofuran‐tethered 2‐iodoanilines give synthetically interesting 2‐(3‐indolylmethyl)phenols in an overall reductive process. Mechanistic studies suggest that this unusual reaction proceeds by carbopalladation of benzofuran giving a 3‐palladated 2, 3‐dihydrobenzofuran intermediate, which then fragments by an uncommon trans ‐elimination of the phenoxide group β to the metal. In this transformation, N, N ‐diisopropylethylamine (DIPEA) acts as a base and as a reducing agent: it regenerates palladium(0) from palladium(II), thus allowing catalytic turnover. Abstract :