Room Temperature Copper-Catalyzed 2-Functionalization of Pyrrole Rings by a Three-Component Coupling Reaction

✍ Scribed by Seung Hwan Cho; Sukbok Chang

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 336 KB
• Volume: 47
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.200705940

✦ Synopsis

The efficient construction of a CÀC bond is an important process in modern synthetic chemistry. [1] In particular, the functionalization of heterocycles such as pyrrole units, which have utility in organic synthesis and medicinal chemistry, [2] relies on the C À C bond forming strategies. A wide range of synthetic strategies involving Friedel-Crafts reactions have been devised. [3] Recently, we developed a Cu-catalyzed three-component coupling reaction of terminal alkynes and sulfonyl azides with amines, alcohols, or water to afford amidines, imidates, and amides, respectively. [4] The reaction was versatile with regard to the substrate scope and the synthetic applicability. The reaction is proposed to proceed through a ketenimine intermediate, which is generated in situ from the triazole cycloadduct upon release of N 2 gas. [5] Our ongoing work in this area led us to propose that the construction of a CÀC bond would be feasible by employing aromatic heterocycles in our multicomponent protocol (Scheme 1).