Direct C-H photoarylation of diazines using aryldiazonium salts and visible-light

Author(s)

Silva, Rodrigo C. ; Villela, Lucas F. ; Brocksom, Timothy J. ; de Oliveira, Kleber T.

• Document type: Journal article
• Source: RSC ADVANCES; v. 10, n. 52, p. 8-pg., 2020-08-25.

Abstract

In this study, direct C-H photoarylation of pyrazine with aryldiazonium salts under visible-light irradiation (blue-LEDs) is described, and additional examples including photoarylations of pyrimidine and pyridazine are also covered. The corresponding aryl-diazines were prepared in yields up to 84% only by mixing and irradiating the reaction with no need for an additional photocatalyst. We demonstrate the efficacy of this protocol by the scope with electron-donor, -neutral, and -withdrawing groups attached at theortho,meta, andparapositions of the aryldiazonium salts; the results are better than those reported for ruthenium-complex mediated photoarylations. Additionally, we demonstrate the robustness of this methodology with a 5 mmol scaled-up experiment. Mechanistic studies were carried out giving support to the proposal of a photocatalyzed approach by an electron donor-acceptor (EDA) complex, also highlighting the crucial role that solvents play in the formation of the EDA complex. (AU)

• FAPESP's process: 18/00106-7 - Photocatalyzed Reactions by using porphyrins and continuous flow conditions: Arylations of heterocycles and activated olefins.
• Grantee: Kleber Thiago de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/00879-6 - Arylation reactions of heterocycles photocatalysed by porphyrins in both batch and continuous flow conditions.
• Grantee: Rodrigo Costa e Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/07276-1 - CEPOF - Optics and Photonic Research Center
• Grantee: Vanderlei Salvador Bagnato
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC