Preference of β-Lactam Formation in Cu(I)-Catalyzed Intramolecular Coupling of Amides with Vinyl Bromides
Qiwu Zhao and Chaozhong Li*
*Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, P. R. China, Email: cligmail.sioc.ac.cn
Q. Zhao, C. Li, Org. Lett., 2008, 10, 4037-4040.
DOI: 10.1021/ol801545a (free Supporting Information)
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A general and highly efficient synthesis of 4-alkylidene-2-azetidinones was achieved by the Cu(I)-catalyzed intramolecular C-N coupling of amides with vinyl bromides. This 4-exo ring closure was found to be fundamentally preferred over other modes (5-exo, 6-exo, and 6-endo) of cyclization under copper catalysis.
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H. Lu, C. Li, Org. Lett., 2006, 8, 5365-5367.
Y. Fang, C. Li, J. Am. Chem. Soc., 2007, 129, 8092-8093.