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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Brønsted Acid-Catalyzed Regioselective Coupling between Azoles and Arylcyclobutenes
Chunxiu Jing1, Juanjuan Wang1, Jie Chang1
1Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710069, China.
Abstract:
Herein, we describe a protocol for Brønsted acid-catalyzed regioselective coupling of azoles such as pyrazoles, 1,2,3-triazole, 1,3,4-triazole, benzotriazole, indazole and tetrazole, to cyclobutenes. These azoles could be directly coupled with various arylcyclobutenes with high site-selectivity, offering a distinct entry to more functionalized cyclobutanes. The usage of inexpensive TsOH ⋅ H2O catalyst, broad substrate scope, and open-air conditions make this protocol practically viable. This study not only contributes a feasible tool for selective functionalization of cyclobutenes, but also provides a strategy to introduce cyclobutane moieties into complex molecules.
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