Structure and Properties of 3-(Diethylboryl)pyridines1
Structure and Properties of 3-(Diethylboryl)pyridines1
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3-(二乙基硼基)吡啶的结构和性质1
DOI：
10.1021/jo960825k
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
S. Yano
中科院分区：
文献类型：
--
作者：
Y. Sugihara;K. Takakura;T. Murafuji;R. Miyatake;K. Nakasuji;Masako Kato;S. Yano
3-(二乙基硼基)吡啶 (1a) 是一种用于制备芳基吡啶的通用原料，尽管硼原子上的空间位阻很小，但其在环境条件下的稳定性值得注意。 1a的1H和13C光谱表明硼基团不仅仅充当π-受体并且硼原子被大约屏蔽。即使与与 π 供体共轭的三价硼原子相比，也为 50 ppm。对 1a 的单晶 X 射线晶体学研究表明，通过分子间硼氮配位键形成了带有空隙的环状四聚体。各种溶剂中的蒸气压渗透压测定表明，1a 在这些溶液中包含四聚体。为了了解其实际结构，进行了3-(2-甲氧基乙氧基)-5-(二乙基硼基)吡啶(1b)的合成及其与1a的打乱实验。需要在 100°C 下加热 24 小时才能达到四聚体中组分分子的扰乱平衡。这意味着 3-(二乙基硼基)吡啶...
3-(Diethylboryl)pyridine (1a), a versatile starting material for the preparation of arylpyridines, is notable for its stability under ambient conditions, in spite of little steric hindrance on the boron atom. 1H and 13C spectra of 1a indicated that the boryl group does not act as a mere π-acceptor and that the boron atom is shielded by ca. 50 ppm even when compared with trivalent boron atoms conjugated with the π-donor. A single-crystal X-ray crystallographic study for 1a revealed formation of a cyclic-tetramer with a void via the intermolecular boron−nitrogen coordination bond. Vapor pressure osmometry in various solvents suggested that 1a comprises the tetramer in these solutions. In order to know the actual structure, synthesis of 3-(2-methoxyethoxy)-5-(diethylboryl)pyridine (1b) and its scrambling experiment with 1a were carried out. Heating at 100 °C for 24 h was required to attain the equilibrium of the scrambling of the component molecules in the tetramers. This means that 3-(diethylboryl)pyridines...