Expedient Synthesis of Substituted Benzoheterocycles using 2‐Butoxy‐2, 3‐dihydrofurans as [4+2] Benzannulation Reagents. Issue 14 (9th May 2016)

• Record Type: Journal Article
• Authors: Liu, Changhui; Huang, Wenbo; Wang, Man; Pan, Bin; Gu, Yanlong
• Is Part Of: Advanced synthesis & catalysis. Volume 358:Issue 14(2016)
• Page Start: 2260
• Page End: 2266
• Publication Date: 2016-05-09
• Subjects: benzannulation -- benzofurans -- carbazoles -- copper -- dihydrofurans -- indoles; Catalysis -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Chemistry -- Periodicals; Chemistry, Technical -- Periodicals; Chemistry -- Periodicals; Catalysis -- Periodicals; Technology, Pharmaceutical -- Periodicals; 547.2
• DOI: 10.1002/adsc.201600185
• Languages: English
• ISSNs: 1615-4150

Abstract

Abstract: 2‐Alkoxy‐2, 3‐dihydrofurans were found to be versatile benzannulation reagents. Indoles can be synthesized in good to excellent yields via the [4+2] annulation of 2‐butoxy‐2, 3‐dihydrofuran with pyrroles catalyzed by copper bromide. With the same protocol, carbazoles can also be obtained when indoles are used as starting material with the aid of p ‐toluenesulfonic acid. This type of benzannulation reagent can also be used to synthesize benzofuran, benzothiophene and naphthalene derivatives in the presence of a catalytic amount of triflic acid in moderate yields. This benzannulation protocol features wide substrate scope and mild reaction condition. Moreover, most of examples have a good regioslectivity. Abstract :