高度に化学選択性の高い三次性アミドの金属フリー還元
Guillaume Barbe1, André B Charette
1Département de chimie, Université de Montréal, P.O. Box 6128, Station Downtown, Montréal, Quebec, Canada H3C 3J7.
Journal of the American Chemical Society
|December 14, 2007
まとめ
本研究は,Hantzschエステルを使用して,三次性アミドをアミンに還元するための金属のない方法を提示しています. この新しいアプローチは,三次アミンを合成するための高機能群耐性を提供します.
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
背景:
- 三次性アミドは,医薬品や有機合成における一般的な機能群である.
- 効率的で選択的な方法で三次アミンに還元する方法は,非常に求められています.
- 既存の還元方法は,しばしば厳しい条件や有毒な反応剤を必要とします.
研究 の 目的:
- 三次性アミドの還元のための新しい,化学選択的,金属のない方法を開発する.
- ハンツシュエステルを温和で持続的な還元剤として利用する.
- アミド還元過程で高い機能群耐性を達成するために.
主な方法:
- トリフローロメタヌスルフォニックアンヒドリドを用いた三次性アミドの活性化.
- 金属のないシステムでハンツシュエステルを使用して活性化アミドを減少させる.
- 結果となる三次アミンの浄化と特徴付け.
主要な成果:
- 様々な三次性アミドを三次性アミンに化学選択的に成功的に還元する.
- 高い機能グループ耐性の実証,敏感な部分の保存.
- 軽度の反応条件と金属触媒の回避.
結論:
- 開発された方法は,三次アミドから三次アミンを合成するための効率的でグリーンな代替手段を提供します.
- ハンツシュエステルは,この変換のための実用的で穏やかな還元剤として機能します.
- この方法論は,価値あるアミン化合物にアクセスするための合成ツールボックスを拡張します.
関連する概念動画
01:13Preparation of Amines: Reduction of Amides and Nitriles
Nitriles can be reduced to primary amines using reducing agents like lithium aluminum hydride or catalytic hydrogenation. The reduction introduces an amino group with an extra carbon in the skeleton. Nitriles are formed from the reaction between alkyl halides and sodium cyanide through the SN2 mechanism. Primary alkyl halides are the preferred substrates to prepare nitriles.
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
01:20Amides to Amines: LiAlH4 Reduction
Amide reduction with strong reducing agents like lithium aluminum hydride proceeds through a nucleophilic acyl substitution to form amines. Primary, secondary, and tertiary amides yield primary, secondary, and tertiary amines, respectively.
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
01:29Preparation of Amines: Reduction of Oximes and Nitro Compounds
Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid.
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
01:38Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
00:55Nitriles to Amines: LiAlH4 Reduction
Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
02:10Reduction of Alkynes to trans-Alkenes: Sodium in Liquid Ammonia
Alkynes can be reduced to trans-alkenes using sodium or lithium in liquid ammonia. The reaction, known as dissolving metal reduction, proceeds with an anti addition of hydrogen across the carbon–carbon triple bond to form the trans product. Since ammonia exists as a gas (bp = −33°C) at room temperature, the reaction is carried out at low temperatures using a mixture of dry ice (sublimes at −78°C) and acetone.
When dissolved in liquid ammonia, an alkali metal, such as sodium, dissociates into a...
When dissolved in liquid ammonia, an alkali metal, such as sodium, dissociates into a...