Hydroboration as an Efficient Tool for the Preparation of Electronically and Structurally Diverse N→B-Heterocycles.
Hydroboration as an Efficient Tool for the Preparation of Electronically and Structurally Diverse N→B-Heterocycles.
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DOI：
10.1002/chem.201602458
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
M. Grandl;Thomas Kaese;A. Krautsieder;Yu Sun;F. Pammer
中科院分区：
文献类型：
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作者：
M. Grandl;Thomas Kaese;A. Krautsieder;Yu Sun;F. Pammer
以2-（邻苯乙烯）吡啶（PhPy）与9h -9-硼比环[3.3.1]壬基（9H-BBN）、BH3⋅THF、HBCl2⋅SMe2、HB(C6 F5)2和9h -9-硼芴衍生物为原料，通过硼氢化反应制备了分子内N→B配位的阶梯型有机硼烷。硼氢化反应在温和条件下产生高度区域选择性的硼酰化反应，产物收率高至优异。实验研究了硼烷的分子结构和电子性质，并结合DFT计算进一步阐明了光学和电子性质差异的来源。共轭体系的电子亲和力可以通过硼烷的变化来控制，而光学性质同样与硼上取代基的类型和分子结构直接相关。广泛的底物范围表明，这种制备方法广泛适用于将化学上不同的硼基引入共轭体系。
Ladder-type organoboranes featuring intramolecular N→B coordination have been prepared through hydroboration of a 2-(ortho-styryl)pyridine (PhPy) with a series of hydroboranes, including 9H-9-borabicyclo[3.3.1]nonyl (9H-BBN), BH3 ⋅THF, HBCl2 ⋅SMe2 , HB(C6 F5 )2 , and a 9H-9-borafluorene derivative. The hydroboration reaction results in highly regioselective borylation under mild conditions and gives the products in good to excellent yields. The molecular structure and electronic properties of the obtained boranes have been experimentally investigated in detail, and complemented with DFT calculations to further elucidate the origin of differences in optical and electronic properties. The electron affinity of the conjugated system can be controlled through variation of the borane, while the optical properties are likewise directly linked to the type and molecular structure of the substituents on boron. The broad substrate range shows that this preparative approach is widely applicable to introduce chemically diverse boryl groups into conjugated systems.