Yewen Fang, Chaozhong Li
Jun 9, 2007
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0
Influential Citations
49
Citations
Journal
Journal of the American Chemical Society
Abstract
The copper-catalyzed intramolecular O-vinylation of γ-bromohomoallylic alcohols was investigated. With 10 mol % of CuI as the catalyst and 20 mol % of 1,10-phenanthroline as the ligand, the reactions of 3-bromo-3-buten-1-ols in refluxing CH3CN led to the convenient formation of the corresponding 2-methyleneoxetanes in good to excellent yields via a 4-exo ring closure. The configuration of the CC bond was nicely retained. This methodology was then successfully extended to the cyclization in 5-exo, 6-exo, and even 6-endo modes. Moreover, the competition experiments revealed that 4-exo cyclization is fundamentally preferred over other modes of cyclization. On the other hand, the corresponding Pd(0)-catalyzed O-vinylation showed the predominance of 5-exo over 4-exo cyclization.