Cobalt-catalyzed 2-(1-methylhydrazinyl)pyridine-assisted cyclization of thiophene-2-carbohydrazides with maleimides: efficient synthesis of thiophene-fused pyridones.

Hua Zhao, Taimin Wang, Zhineng Qing, Hongbin Zhai

Chemical communications (Cambridge, England) 2020 May 21

filter terms:

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.

Citation

Hua Zhao, Taimin Wang, Zhineng Qing, Hongbin Zhai. Cobalt-catalyzed 2-(1-methylhydrazinyl)pyridine-assisted cyclization of thiophene-2-carbohydrazides with maleimides: efficient synthesis of thiophene-fused pyridones. Chemical communications (Cambridge, England). 2020 May 21;56(41):5524-5527