N,N-bis (シリロキシ) エナミンの構造とステレオダイナミクス
Alexander A Tishkov1, Alexander D Dilman, Valery I Faustov
1N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Leninsky Prosp. 47, Moscow, Russian Federation. tishkov@cacr.ioc.ac.ru
Journal of the American Chemical Society
|September 19, 2002
まとめ
この研究では,N,N-bis(silyloxy) enamineをシミュレートし,そのユニークな構造とステレオダイナミクスを明らかにしました. 計算的および物理的な方法により,低C-N回転障壁と高窒素ピラミダ性が確認され,その反応性が説明されました.
科学分野:
- 有機化学 オーガニック・ケミストリー
- コンピューティング・ケミストリー
- 物理化学 物理化学
背景:
- N,N-bis ((シリロキシ) エナミンは,高度に反応性の高い化合物の新しいクラスを表しています.
- その構造的および動的性質を理解することは,合成アプリケーションにとって極めて重要です.
研究 の 目的:
- N,N-bis (シリロキシ) エナミンの構造とステレオダイナミクスの解明.
- 計算上の発見を実験的スペクトロスコピクおよび結晶学的データと相関させる.
主な方法:
- 密度関数理論 (DFT) PBE/TZP 構造および動的シミュレーションのための方法.
- 実験的な検証は,X線分析,ダイナミックな核磁気共振 (NMR) スペクトロスコピー,UVスペクトロスコピーを用いて行われました.
主要な成果:
- 計算された構造的および動的パターンは,実験観察と正確に一致しました.
- C-N単一結合の周りを回転させるための低バリアが特定されました.
- 軽微なn-π結合と高い反転障壁が決定されました.
- 窒素原子の高ピラミダ性が確認されました.
結論:
- この研究は,N,N-bis ((silyloxy) enamineのステレオダイナミクスの包括的な理解を提供します.
- 窒素のピラミダ性を含むユニークな構造的特徴は,観測された高い反応性を説明します.
- DFTシミュレーションは,新しいエナミンクラスの行動を予測するための信頼できるツールとして機能します.
関連する概念動画
04:01VSEPR Theory and the Effect of Lone Pairs
Effect of Lone Pairs of Electrons on Molecule Geometry
02:06Newman Projections
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as conformers.
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
02:34Molecular Structure and Acidity
An acid can be deprotonated to form a conjugate base or an anion. If the produced anion is more stable, then the acid is stronger. On the contrary, if the anion is unstable, then the acid is weaker. Hence, to determine the acidity of the compound, the stability of its conjugate base is studied using various factors.
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
01:19Structure of Amines
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...