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Synthesis 2019; 51(20): 3859-3864
DOI: 10.1055/s-0037-1611895
DOI: 10.1055/s-0037-1611895
paper
Aryl Ketone Mediated Photoinduced Radical Coupling for the Alkylation of Benzazoles Employing Saturated Heterocyclic Compounds
This research was supported by a research grant from the Astellas Foundation for Research on Metabolic Disorders, a program of the YU Project for Formation of the Core Research Center, and the Japan Society for the Promotion of Science (JSPS, KAKENHI Grant Number JP18K05107).Further Information
Publication History
Received: 12 May 2019
Accepted after revision: 01 July 2019
Publication Date:
31 July 2019 (online)
Abstract
An aryl ketone mediated synthesis of 2-alkylated benzazoles was achieved via radical coupling under photoirradiation starting from saturated heterocycles and 2-sulfonylated benzazoles, such as benzothiazoles, benzoxazole, and benzimidazole. Heterocyclic compounds, including a cyclic ether, azacycles, and tetrahydrothiophene, were applicable, and the benzazole unit was site-selectively installed at the carbon center proximal to the heteroatom. The present transformation takes place at ambient temperature under neutral reaction conditions without the aid of any metallic catalysts or reagents.
Supporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/s-0037-1611895.
- Supporting Information
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- 18 Compounds 3e and 7 might not be stable when heated as they became colored as they melted.
For representative reviews, see:
For books on metal-catalyzed coupling reactions, see:
For representative reports on metal-catalyzed coupling reactions for the derivatization of benzazoles, see:
For metal-catalyzed alkylations of benzazoles, see:
For other alkylation methods of benzazoles, see:
For related examples of photoinduced C(sp3)–H functionalizations from our group, see:
For related reports of aryl ketone mediated photoinduced C(sp3)–H functionalizations from other research groups, see: