マグネシウムエナマイドをアルキル塩化物およびフッ化物でアルキル化することで
Takuji Hatakeyama1, Shingo Ito, Masaharu Nakamura
1Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Journal of the American Chemical Society
|October 13, 2005
まとめ
マグネシウムエナミドの化学反応は,ケトンの効率的なアルファアルキル化を可能にします. この反応は高いステレオ化学的反転で進行し,光学的に活性な化合物を生成するのに価値があります.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成化学 合成化学とは
- ステレオ化学 ステレオ化学
背景:
- エナミドは,汎用性の高い合成中間物質である.
- ステレオセレクティブ合成は,医薬品と微細化学品にとって極めて重要です.
- カルボニル化合物のアルキル化は,ステレオ制御においてしばしば課題に直面する.
研究 の 目的:
- マグネシウムエナミドを用いたケトンのアルファアルキル化のための新しい方法の開発.
- アルキル化反応のステレオ化学的結果を調査する.
- 光学的に活性なケトンを生産するこの方法の有用性を評価する.
主な方法:
- N-2-(N',N'-ダイエチラミノ) エチルイミンからマグネシウムエナミドを調製する.
- マグネシウムエナミドが,主/副次アルキル塩化物または主アルキルフッ化物と反応する.
- 中間物質の水解により,アルファ・アルキル化ケトンが得られる.
主要な成果:
- この反応により,アルファ-アルキル化ケトンが良好から優れた収穫量で得られる.
- 高レベルのステレオ化学的逆転が,電性炭素中心で観察されました.
- この方法は,一次性および二次性アルキルハリド/フッ素の両方に対して有効です.
結論:
- マグネシウムエナミドの化学反応は,アルファ-アルキル化ケトンへの効率的な経路を提供します.
- 反応の高いステレオ反転により,非対称合成に適しています.
- この方法論は,価値ある光学活性化合物の生産に適用することができます.
さらに関連する動画
関連する概念動画
01:01Acid Halides to Carboxylic Acids: Hydrolysis
Hydrolysis of acid halides is a nucleophilic acyl substitution reaction in which acid halides react with water to give carboxylic acids. The reaction occurs readily and does not require acid or a base catalyst.
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...
01:12Acid Halides to Esters: Alcoholysis
Alcoholysis is a nucleophilic acyl substitution reaction in which an alcohol functions as a nucleophile. Acid halides react with alcohol to produce esters. The mechanism proceeds in three steps:
01:07Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
01:28Amides to Carboxylic Acids: Hydrolysis
Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
01:08Nitriles to Carboxylic Acids: Hydrolysis
Nitriles undergo acid-catalyzed hydrolysis or base-catalyzed hydrolysis to form a carboxylic acid. These reactions proceed via an amide intermediate.
01:19Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.