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Phosphine-Catalyzed Annulations Based on [3+3] and [3+2] Trapping of Ketene Intermediates with Thioamides

Yu-Hao Wang, Zhen-Ni Zhao, Subarna Jyoti Kalita and Yi-Yong Huang*

*Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China, Email:

Y.-H. Wang, Z.-N. Zhao, S. J. Kalita, Y.-Y. Huang, Org. Lett., 2021, 23, 8147-8152.

DOI: 10.1021/acs.orglett.1c02803

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An allenyl imide and alkynoates bearing good leaving groups are used as ketene precursors in tandem conjugate addition-elimination reactions promoted by nucleophilic phosphine catalysts. By utilizing thioamides as 1S,3N-bis-nucleophiles, [3+3] and [3+2] annulations provide rapid access to 1,3-thiazin-4-ones and 5-alkenyl thiazolones in high yields, respectively.

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Key Words

1,3-thiazin-4-ones, thiazolones, N-heterocycles, S-heterocycles

ID: J54-Y2021