Stereloselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis
Stereloselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis
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DOI：
10.1002/anie.200906830
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Njardarson, Jon T.
中科院分区：
文献类型：
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作者：
Brichacek, Matthew;Batory, Lindsay A.;Njardarson, Jon T.
我们研究计划的核心部分是开发广泛适用的原子效率合成方法，以产生结构复杂性。我们最近报道了一种新的铜催化乙烯基环氧乙烷环扩展，使用市售的、结构简单且空气稳定的铜 (II) 催化剂。 1 这些研究证明了该反应对于多种底物都是成功的。这些早期研究中缺少专注于评估环扩张的立体选择性潜力的实验。本文提出的研究旨在解决这一点，并了解在扩环过程中断裂的环氧乙烷CO键是否可以立体选择性地转移到烯烃末端。此外，拟议研究的另一个好处是关键的机制见解，可以进一步阐明这种独特的催化环膨胀反应的确切机制。如果乙烯基环氧乙烷确实可以使用铜催化剂进行立体选择性环扩展，那么这种新反应的实际效益将显着扩大。此外，这种转化在效率和范围方面将与立体选择性获得 2, 5-二氢呋喃的现有方法相媲美。
The central part of our research program is the development of broadly applicable atom-efficient synthetic methods to generate structural complexity. We recently reported a new copper-catalyzed ring expansion of vinyl oxiranes using commercially available, structurally simple and air stable copper (II) catalysts. 1 These studies demonstrated the success of this reaction for a broad range of substrates. Missing from these early studies were experiments focused on assessing the stereoselective potential of the ring expansion. The studies presented herein are aimed at addressing this point and to learn if the oxirane CO bond that is broken during the ring expansion could be stereoselectively transferred to the olefin terminus. Moreover, an added benefit to the proposed studies would be critical mechanistic insights that could shed further light on the exact mechanism of this unique catalytic ring expansion reaction. If vinyl oxiranes can indeed be stereoselectivity ring expanded using copper catalysts then the practical benefits of this new reaction would be significantly expanded. Also this transformation would rival existing methods2 to stereoselectively access 2, 5-dihydrofurans in terms of efficiency and scope.