Cobalt-catalyzed 2-(1-methylhydrazinyl)pyridine-assisted cyclization of thiophene-2-carbohydrazides with maleimides: efficient synthesis of thiophene-fused pyridones. Issue 41 (16th April 2020)

• Record Type: Journal Article
• Authors: Zhao, Hua; Wang, Taimin; Qing, Zhineng; Zhai, Hongbin
• Is Part Of: Chemical communications. Volume 56:Issue 41(2020)
• Page Start: 5524
• Page End: 5527
• Publication Date: 2020-04-16
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/d0cc01582b
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : A cobalt-catalyzed direct C–H/N–H functionalization of thiophene-2-carbohydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine (MHP) as an easily removable bidentate directing group has been developed. Abstract : A cobalt-catalyzed direct C–H/N–H functionalization of thiophene-2-carbohydrazides with maleimides by utilizing 2-(1-methylhydrazinyl)pyridine (MHP) as an easily removable bidentate directing group has been developed. This formal [4+2] cycloaddition has been achieved for the first time, and it provides an alternative and versatile approach to construct thiophene-fused pyridones using an inexpensive cobalt catalyst. The C–H/N–H activation cascade protocol showed a high efficiency and a broad substrate scope, and the products were obtained in good to excellent yields.