Issue 11, 2024

Thiourea as a precatalyst for the electron donor–acceptor complex photoactivation platform of oxime esters

Abstract

A novel electron donor–acceptor (EDA) complex catalysis strategy has been developed, employing N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea as a pre-catalyst and a base as a pre-catalyst initiation switch to generate iminyl radical intermediates from oxime esters via a single-electron reduction process under blue LED irradiation. This approach not only in situ converts a cost-effective and stable precursor into an electron donor for the catalytic system but also achieves the regeneration of the donor species. By utilizing 2–5 mol% of thiourea, a wide range of nitrogen-containing compounds, including pyrrolines, ketonitriles, phenanthridines, pyridines, and quinolines, were successfully synthesized, emphasizing the versatility of this approach. The pivotal roles of the pre-catalyst, base, and blue LED irradiation were verified through control experiments. Mechanistic studies and density functional theory calculations indicate that the generated thiouronyl anions serve as catalytic electron-donor species under blue light irradiation, enabling the single-electron reduction of oxime esters to form iminyl radical intermediates.

Graphical abstract: Thiourea as a precatalyst for the electron donor–acceptor complex photoactivation platform of oxime esters

Supplementary files

Article information

Article type
Research Article
Submitted
05 Mar 2024
Accepted
17 Apr 2024
First published
18 Apr 2024

Org. Chem. Front., 2024,11, 3204-3213

Thiourea as a precatalyst for the electron donor–acceptor complex photoactivation platform of oxime esters

H. Mao, Y. Zhang, H. Cao, Q. Shi, Y. Lan, J. Chang and B. Zhu, Org. Chem. Front., 2024, 11, 3204 DOI: 10.1039/D4QO00424H

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