A Heterogeneous Gold(I)-Catalyzed [2 + 2 + 1] Annulation of Terminal Alkynes, Nitriles, and Oxygen Atoms Leading to 2,5-Disubstituted Oxazoles
Weisen Yang, Rongli Zhang, Feiyan Yi and Mingzhong Cai*
*Key Laboratory of Functional Small Organic Molecule, Ministry of Education and College of Chemistry & Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. China, Email: mzcaijxnu.edu.cn
W. Yang, R. Zhang, F. Yi, M. Cai, J. Org. Chem., 2017, 82, 5204-5211.
DOI: 10.1021/acs.joc.7b00386 (free Supporting Information)
An MCM-41-immobilized phosphine-gold(I) complex as catalyst enables a [2 + 2 + 1] annulation of terminal alkynes, nitriles, and oxygen atoms using 8-methylquinoline N-oxide as oxidant under mild conditions to provide 2,5-disubstituted oxazoles in very good yields with broad substrate scope. The heterogeneous catalyst can easily be recovered by simple filtration and recycled for at least eight times without significant loss of activity.
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