Preference of 4-<i>exo</i> Ring Closure in Copper-Catalyzed Intramolecular Coupling of Vinyl Bromides with Alcohols
作者:Yewen Fang、Chaozhong Li
DOI:10.1021/ja072793w
日期:2007.7.1
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
研究了铜催化的γ-溴代高烯丙醇的分子内O-乙烯基化。以 10 mol % CuI 为催化剂,20 mol % 1,10-菲咯啉为配体,3-bromo-3-buten-1-ols 在回流 CH3CN 中的反应导致相应的 2-亚甲基氧杂环丁烷通过 4-exo 闭环获得良好的产率。CC 键的配置很好地保留了下来。该方法随后成功扩展到 5-exo、6-exo 甚至 6-endo 模式的环化。此外,竞争实验表明,4-exo 环化从根本上优于其他环化模式。另一方面,相应的 Pd(0) 催化的 O-乙烯基化显示 5-exo 超过 4-exo 环化的优势。