Preference of 4-exo Ring Closure in Copper-Catalyzed Intramolecular Coupling of Vinyl Bromides with Alcohols
Yewen Fang and Chaozhong Li*
*Joint Laboratory of Green Synthetic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China, Email: cligmail.sioc.ac.cn
Y. Fang, C. Li, J. Am. Chem. Soc., 2007, 129, 8092-8093.
DOI: 10.1021/ja072793w (free Supporting Information)
The intramolecular O-vinylation of γ-bromohomoallylic alcohols with 10 mol % of CuI as the catalyst and 20 mol % of 1,10-phenanthroline as the ligand in refluxing MeCN led to the convenient formation of the corresponding 2-methyleneoxetanes in good to excellent yields via a 4-exo ring closure. 4-exo cyclization is preferred over other modes of cyclization.
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Q. Zhao, C. Li, Org. Lett., 2008, 10, 4037-4040.
Q. Zhao, L. Li, Y. Fang, D. Sun, C. Li, J. Org. Chem., 2009, 74, 459-462.