Synthesis of Stable Silaaromatic Compounds by Taking Advantage of Steric Protection

利用空间保护合成稳定的硅杂芳族化合物

• 批准号: 08454197
• 负责人: OKAZAKI Renji
• 金额: $ 5.06万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454197/
• 关键词: Aromaticity; Silanaphthalene; X-ray crystallography; Bond delocalization; ^<29>Si NMR

Aromatic hydrocarbons such as benzene and naphthalene play a very important role in organic chemistry, but silaaromatic compounds where some of the skeletal carbons are replaced by silicon is very unstable and there has been no example isolation of such compounds. In this study, we have succeeded in the synthesis of the first example of a silaromatic compound, 1.e., 2-silanapthalene 1, by taking advantage of kinetic stabilization afforded by a sterically protecting group, 2,4,6-tris[bis (trimethylsilyl) methyl]phenyl (Tbt group). Reduction of dichlorinated tetrahydronapthalene followed by reaction with TbtLi, Bromination, reduction, and rebromination gave the direct precursor of 1. Debromination of 1 with t-BuLi in hexane gave 1 as colorless crystals. Although 1 reacts with water and oxygen very rapidly, it is thermally quite stable. The structure was established by ^1H and ^<29>Si NMR and X-ray crystallography. Of particular note is the ^<29>Si signal, which appear at delta 87.4, indicating the presence of sp_2 Si. Furthermore, the ^1J coupling constants of Cl-Si and Si-C3 are 92 and 76 Hz, respectively, clearly indicating that there is some delocalization of pi-electrons in the silanaphthalene ring. Another 2-silanaphthalene having 2,6-bis[bis(trimethylsilyl)methyl]-4-tris[(trimethylsilyl)methyl]phenyl group was also synthesized.

芳烃如苯和萘在有机化学中起着非常重要的作用，但是其中一些骨架碳被硅取代的硅杂芳族化合物非常不稳定，并且还没有这样的化合物的实例分离。在这项研究中，我们成功地合成了第一个硅芳族化合物的例子，1.e.，2-硅烷萘1，通过利用由空间保护基团2，4，6-三[双（三甲基甲硅烷基）甲基]苯基（Tbt基团）提供的动力学稳定。二氯四氢萘经还原、溴化、还原、再溴化得到1的直接前体。1用t-BuLi在己烷中脱溴得到无色晶体1。虽然1与水和氧气反应非常迅速，但它是热稳定的。其结构由^1H和1H <29>Si NMR以及X射线晶体学确定。特别值得注意的是<29>出现在Δ 87.4处的Δ Si信号，其指示sp_2Si的存在。此外，Cl-Si和Si-C3的^1J耦合常数分别为92和76 Hz，这清楚地表明硅萘环中的π电子存在一定程度的离域。还合成了另一种含2，6-双[双（三甲基硅基）甲基]-4-三[（三甲基硅基）甲基]苯基的2-硅萘。

项目成果

N.Tokitoh: "A Stable Neural Silaaromatic Compound, 2-{2,4,6-Tris[bis(trimethylsilyl)methyl]phenyl}-2-silanaphthalene" J.Am.Chem.Soc.119. 6951-6952 (1997)

N.Tokitoh：“一种稳定的神经硅芳香族化合物，2-{2,4,6-三[双(三甲基硅基)甲基]苯基}-2-硅萘”J.Am.Chem.Soc.119。

N.Takeda: "Reaction of a Sterically Hindered Silylene with Isocyanides:The First Stable Silyence-Lcwis Base Complexes" J.Am.Chem.Soc.119. 1456-1457 (1997)

N.Takeda：“空间位阻硅烯与异氰化物的反应：第一个稳定的 Silyence-Lcwis 碱配合物”J.Am.Chem.Soc.119。

N.Takeda: "Reaction of a Sterically Hindered Silylene with Isocyanides:The First Stable Silylene-Lewis Base Complexes." J.Am.Chem.Soc.(印刷中).

N.Takeda：“空间位阻硅烯与异氰化物的反应：第一个稳定的硅烯-路易斯碱配合物”（J.Am.Chem.Soc）。

N.Takeda.: "Reaction of a Sterically Hindered Silylene with Isocyanides : The First Stable Silylene-Lewis Base Complexes" J.Am.Chem.Soc.119. 1456-1457 (1997)

N.Takeda.：“空间位阻亚硅基与异氰化物的反应：第一个稳定的亚硅基-路易斯碱配合物”J.Am.Chem.Soc.119。

N.Tokitoh: "A Stable Neutral Silaaromatic Compound,2-{2,4,6-Tris〔bis(trimethylsilyl)methyl〕-phenyl}-2-silanaphthalene" J.Am.Chem.Soc.119. 6951-6952 (1997)

N.Tokitoh：“稳定的中性硅芳香族化合物，2-{2,4,6-三[双(三甲基硅基)甲基]-苯基}-2-硅萘”J.Am.Chem.Soc.119 ( 1997）