トロピリウムイオン媒介によるアミンのα-シアネーション
Julia M Allen1, Tristan H Lambert
1Department of Chemistry, Columbia University, New York, New York 10027, United States.
Journal of the American Chemical Society
|January 6, 2011
まとめ
トロピリウムイオンは,基質をイミニウムイオンに酸化することによって,アミンの直接アルファシアン化を可能にします. この効率的な方法は,単純な副産物を持つアミノニトリルを生成します.
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:
- アミンのアルファシアネーションは,有機合成における重要な変換である.
- 既存の方法は,しばしば厳しい条件や特殊な反応剤を必要とします.
研究 の 目的:
- アミンのアルファシアン化のための新しく効率的な方法を開発する.
- アミン機能化における酸化剤としてのトロピリウムイオンの有用性を調査する.
主な方法:
- トロピリウムイオンは,シアン酸カリウム (KCN) の存在下で,さまざまなアミン基板の直接アルファシアン化を媒介するために使用されました.
- この反応は,アミンをイミニウムイオンに酸化し,その後,塩をシアン化物でメタテシスします.
- この方法は,グラムスケール合成を含む13の異なる基板で実証されました.
主要な成果:
- 様々なアミンの前駆体からアミノニトリルの合成を成功させた.
- この反応により,簡単に除去可能な副産物であるサイクロヘプタトリエンとテトラフルオロボラートカリウムが生成されます.
- トロピリウムイオンによって媒介された酸化アザ-コップの再編成も実証されました.
結論:
- トロピリウムイオンは,アミンのアルファシアン化のための温和で効果的な反応剤を提供します.
- この方法は,アミノニトリル化合物を構築するための合成化学者のツールキットに貴重な追加を提供します.
- この反応の効率と単純な処理は,その実用的な応用性を高めます.
関連する概念動画
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...
01:19Amines to Amides: Acylation of Amines
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
01:28Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
01:22Preparation of 1° Amines: Azide Synthesis
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
01:07Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
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.