Pd-Catalyzed Highly Enantioselective Synthesis of Planar Chiral Ferrocenylpyridine Derivatives
Pd-Catalyzed Highly Enantioselective Synthesis of Planar Chiral Ferrocenylpyridine Derivatives
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DOI：
10.1021/acs.organomet.5b00730
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发表时间：
2015-09
期刊：
影响因子：
2.8
通讯作者：
D. Gao;C. Zheng;Q. Gu;S. You
中科院分区：
文献类型：
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作者：
D. Gao;C. Zheng;Q. Gu;S. You
通过pd催化的分子内C-H基化反应，高效合成了平面手性二茂铁基吡啶衍生物，并对多种底物获得了定量产率和良好的对映选择性。值得注意的是，催化剂负载可以降低到0.2 mol %，这代表了不对称C-H键活化的最高催化效率（TON高达495）。这些化合物可以很容易地转化为吡啶n -氧化物，在中环氧化物的不对称开孔中表现出很好的催化活性。此外，还进行了计算研究，以澄清优异的对映体选择性的来源。大规模合成和低催化剂负载的相容性应增强当前方法合成应用的实用性。
A highly efficient synthesis of planar chiral ferrocenylpyridine derivatives via Pd-catalyzed intramolecular C–H arylation was developed, and quantitative yields and excellent enantioselectivity were obtained for a wide range of substrates. Notably, the catalyst loading could be lowered to 0.2 mol %, which represents the highest catalytic efficiency found for asymmetric C–H bond activation (TON up to 495). These compounds could be easily transformed to pyridine N-oxides, displaying promising catalytic reactivity in the asymmetric opening of meso-epoxide. Moreover, computational investigations were conducted to clarify the origin of the excellent enantioselectivity. The compatibility of large-scale synthesis and low catalyst loading should enhance the practicality of the synthetic application of the current method.