Cobalt-catalyzed electrooxidative C-H/N-H [4+2] annulation with ethylene or ethyne

• Published in: Nature communications Vol. 9; no. 1; pp. 798 - 7
• Main Authors: Tang, Shan, Wang, Dan, Liu, Yichang, Zeng, Li, Lei, Aiwen
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.02.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/403/934; 639/638/549/933; 639/638/77/886; Amides; Aromatic compounds; Carbon; Chemical reactions; Chemicals; Cobalt; Dehydrogenation; Efficiency; Electrochemistry; Ethylene; Fine chemicals; Functional groups; Humanities and Social Sciences; multidisciplinary; Organic chemistry; Oxidants; Oxidation; Oxidizing agents; Recycling; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-03246-4

Ethylene and ethyne are among the simplest two-carbon building blocks. However, quite limited methods can be applied to incorporate ethylene or ethyne into fine chemicals. Here we demonstrate a cobalt-catalyzed dehydrogenative C–H/N–H [4+2] annulation of aryl/vinyl amides with ethylene or ethyne by using an electrochemical reaction protocol. Significantly, this work shows an example of electrochemical recycling of cobalt catalyst in oxidative C–H functionalization reactions, avoiding the use of external chemical oxidants and co-oxidants. The electrochemical method provides a reliable and safe way for incorporating gas-phase ethylene or ethyne into fine chemicals. High reaction efficiency and good functional group tolerance are observed under divided electrolytic conditions. Catalytic methodologies that incorporate commodity chemicals ethylene and ethyne into fine chemicals are quite limited. Here, the authors show a cobalt-catalyzed electrochemical C-H/N–H [4+2] annulation of aryl/vinyl amides with ethylene or ethyne to produce N -heterocycles in absence of oxidants.