Remote Meta-C-H Activation Using a Pyridine-Based Template: Achieving Site-Selectivity via the Recognition of Distance and Geometry.
Remote Meta-C-H Activation Using a Pyridine-Based Template: Achieving Site-Selectivity via the Recognition of Distance and Geometry.
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DOI：
10.1021/acscentsci.5b00312
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发表时间：
2015-10-28
影响因子：
18.2
通讯作者：
Yu JQ
中科院分区：
文献类型：
--
作者：
Chu L;Shang M;Tanaka K;Chen Q;Pissarnitski N;Streckfuss E;Yu JQ
在过去的半个世纪中，吡啶基被广泛用于直接过渡金属催化的C-H活化反应。这些环金属化过程中涉及的典型循环过渡态仅能够激活邻位C-H键。在这里，我们报告说，通过设计定向模板的距离和几何形状，吡啶适合直接苄基和苯乙醇的间位C-H活化。该模板利用更强的 σ 配位吡啶将 Pd 催化剂招募到所需的位点进行功能化。 U 形结构可适应高度紧张的类环芳过渡态。这一进展说明了通过识别有机分子中现有官能团和多个 C-H 键之间的远端和几何关系来实现 C-H 活化的位点选择性的潜力。 C−H 激活的位点选择性是通过识别有机分子中现有官能团和多个 C−H 键之间的远端和几何关系来实现的。
The pyridyl group has been extensively employed to direct transition-metal-catalyzed C–H activation reactions in the past half-century. The typical cyclic transition states involved in these cyclometalation processes have only enabled the activation of ortho-C–H bonds. Here, we report that pyridine is adapted to direct meta-C–H activation of benzyl and phenyl ethyl alcohols through engineering the distance and geometry of a directing template. This template takes advantage of a stronger σ-coordinating pyridine to recruit Pd catalysts to the desired site for functionalization. The U-shaped structure accommodates the otherwise highly strained cyclophane-like transition state. This development illustrates the potential of achieving site selectivity in C–H activation via the recognition of distal and geometric relationship between existing functional groups and multiple C–H bonds in organic molecules. Site selectivity in C−H activation is achieved via recognition of distal and geometric relationship between existing functional groups and multiple C−H bonds in organic molecules.