Replacing sulfuric acid with water in electrochemical metal-free mild aromatic C–H amidation: a direct route to N-phenylamides

Replacing sulfuric acid with water in electrochemical metal-free mild aromatic C–H amidation: a direct route to N-phenylamides Full article

Journal

Organic Chemistry Frontiers
ISSN: 2052-4110 , E-ISSN: 2052-4129

Output data

Year: 2024, Volume: 11, Pages: 5820-5830 Pages count : 11 DOI: 10.1039/d4qo01296h

Authors

Kononov Alexander I. ¹ , Strekalova Sofia O. ¹ , Morozov Vladimir I. ¹ , Boyko Konstantin V. ^2,3 , Timashev Vladimir I. ^4,3 , Medvedev Michael G. ^5,3 , Babaeva Olga B. ¹ , Kobeleva Ekaterina V. ¹ , Ivshin Kamil A. ¹ , Babaev Vasily M. ¹ , Budnikova Yulia H. ¹

Affiliations

1	Arbuzov Institute of Organic and Physical Chemistry, Kazan, 420088 Russia
2	Mendeleev University of Chemical Technology of Russia, Moscow, 125047 Russia
3	Zelinsky Institute of Organic Chemistry, Moscow, 119991, Russia
4	Lomonosov Moscow State University, Moscow, 119991 Russia
5	National Research University Higher School of Economics, Moscow, 101000 Russia

In this work, we describe a mild electro-oxidative metal-, oxidant- and acid-free direct amidation of aromatic C–H bonds using nitrile solvents as a source of amide and amine moieties. We show that carrying out the reaction in a divided cell makes it possible to eliminate the use of an acid used in previous attempts, enabling at the same time this reaction for easily reducible substrates and paired electrosynthesis. This electrochemical approach was demonstrated on 60 examples of N-phenylamides, including propanil, which has not been obtained under electrochemical conditions so far, and 12 examples of benzoxazoles; it is also amenable to gram-scale synthesis. Mechanistic studies (voltammetry, EPR, and quantum chemical calculations) revealed that the process is initiated by the formation of hydroxyl radicals from residual water molecules on the anode, which attack the nitrile solvent, and the resulting amide radicals add to the arene.

Kononov A.I. , Strekalova S.O. , Morozov V.I. , Boyko K.V. , Timashev V.I. , Medvedev M.G. , Babaeva O.B. , Kobeleva E.V. , Ivshin K.A. , Babaev V.M. , Budnikova Y.H.
Replacing sulfuric acid with water in electrochemical metal-free mild aromatic C–H amidation: a direct route to N-phenylamides
Organic Chemistry Frontiers. 2024. V.11. P.5820-5830. DOI: 10.1039/d4qo01296h WOS Scopus OpenAlex

≡ Web of science:	WOS:001303102700001
≡ Scopus:	2-s2.0-85202958555
≡ OpenAlex:	W4402052422