スピロ・ディホスフィンの合成と,ケトンの非対称的水素化におけるその応用
Jian-Hua Xie1, Li-Xin Wang, Yu Fu
1State Key Laboratory and Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China.
Journal of the American Chemical Society
|April 10, 2003
まとめ
新種のスピロ・ディホスフィン・リガンドを含むルテニウム複合体は,非対称な水素化において例外的な性能を示している. これらの触媒は,様々なケトン基板に対して高い活性とエナチオ選択性を達成します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- アシンメトリック・シンセシス
背景:
- キラル・ディホスフィン・リガンドは,非対称な触媒作用において極めて重要です.
- スパイロ・スキャフォールドは,リガンド設計のためのユニークな構造特性を提供します.
研究 の 目的:
- 新規のキラル・ディホスフィン・リガンドを合成するために,スパイロ・スキャフォールドを特徴とする.
- 非対称的水素化におけるこれらのリガンドとルテニウム複合体の触媒性能を評価する.
主な方法:
- スパイロ基のキラル・ディホスフィン・リガンドの合成.
- ルテニウム複合体の製造.
- 様々なケトン (アロマティック,ヘテロアロマティック,α,β-不飽和) の非対称な水素化.
主要な成果:
- ルテニウム複合体は非常に高い触媒活性を示した (基板対触媒比は10万まで).
- 特殊なエナチオセレクティビティが達成されました (エナチオメア過剰は99.5%まで).
- 触媒は,幅広いケトン基板に対して有効でした.
結論:
- 開発されたスピロ・ディホスフィン・リガンドは,非対称な水素化に非常に効果的です.
- これらのリガンドのルテニウム複合体は,ケトン還元のための強力な新種の触媒を表しています.
- この研究は,効率的なエナチオセレクティブ合成のためのツールキットを拡張します.
関連する概念動画
01:15Carboxylic Acid Derivatives: Overview
Carboxylic acid derivatives are formed by replacing the hydroxyl group of carboxylic acids with a different functional group. The most common carboxylic acid derivatives are:
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...
01:07Preparation of Acid Anhydrides
One of the methods for preparing symmetrical or unsymmetrical acid anhydrides involves the treatment of acid chlorides with the sodium salt of carboxylic acids. The reaction proceeds via a nucleophilic acyl substitution.
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
01:15Acid-Catalyzed Aldol Addition Reaction
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.
01:14Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
01:35Loss of Carboxy Group as CO2: Decarboxylation of Malonic Acid Derivatives
Just like β-keto acids—which upon thermal decarboxylation form ketones—β-dicarboxylic acids undergo decarboxylation to generate monocarboxylic acids with the liberation of carbon dioxide.