ハイドロキシアミンを用いたアルケンとアルキンの分子間コペ型水素アミネーション
Joseph Moran1, Serge I Gorelsky, Elena Dimitrijevic
1Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, ON, Canada.
Journal of the American Chemical Society
|December 5, 2008
まとめ
この研究は,ヒドロキシラミンと不飽和化合物の間の金属と酸のない反応のための新しいCope型ヒドロアミネーションを導入します. この方法は,オキシームとN-アルキルヒドロキシラミンを効率的に合成し,合成の可能性を拡大します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 合成方法論 合成方法論
- カタリシス カタリシス カタリシス
背景:
- ハイドロアミナーション反応は,窒素を含む化合物の合成に不可欠である.
- 既存の方法は,しばしば厳しい条件,金属触媒,または強い酸を必要とします.
- より穏やかで,より汎用的な水素アミネーションプロトコルの開発は非常に望ましい.
研究 の 目的:
- 金属や酸を含まないコップ型水素酸化反応を開発する.
- ハイドロキシラミンとアルケン,アルキンとの分子間反応を調査する.
- この新しい合成方法の範囲,限界,およびメカニズム的側面を調査する.
主な方法:
- 使用した水性ヒドロキシラミンと様々なアルケーン/アルキン.
- 反応最適化と添加物スクリーニング (例えば,シアノボロヒドリドナトリウム) を採用しています.
- 機械的洞察のための密度関数理論 (DFT) の計算と並行して実験的研究を実施しました.
主要な成果:
- アルキンからオキシームとN-アルキルヒドロキシラミンからストレートアルケーンから効率的な合成.
- ヴィニラレンとの反応性が実証され,電子特性に基づく枝分かれまたは線形製品が得られる.
- 共通の保護群と機能ハンドルとの互換性を特定しました.
- DFT分析は,N-オキシド中間物質における陽子伝達の重要な役割を明らかにした.
結論:
- 開発されたコップ型水素アミネーションは,価値ある窒素を含む分子を合成するための温和で効果的な経路を提供します.
- この反応は,ビニラレンとの予測可能な地域選択性を示す.
- 機械的理解は,特定の中間物質と陽子転送のステップの重要性を強調します.
関連する概念動画
01:14Amines to Alkenes: Cope Elimination
Cope elimination reaction involves the conversion of tertiary amines to alkene using hydrogen peroxide under thermal conditions, as depicted in figure 1.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Introduction
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
01:16Amines to Alkenes: Hofmann Elimination
Alkenes can be obtained from amines via an E2 elimination. The amine is first converted into a good leaving group, such as a quaternary ammonium salt. This is accomplished by treating the amine with an excess of alkyl halide, which results in a halide salt. Next, the halide salt is transformed into a hydroxide salt that functions as a base to enable elimination.
Under thermal conditions, the hydroxide can abstract a proton from the β carbon; this generates an alkene with the simultaneous...
Under thermal conditions, the hydroxide can abstract a proton from the β carbon; this generates an alkene with the simultaneous...
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
01:16Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
Primary amines react with carbonyl compounds—aldehydes and ketones—to generate imines. Imines consist of a C=N double bond and are named Schiff bases after its discoverer—the German chemist Hugo Schiff. On the other hand, secondary amines react with carbonyl compounds to give enamines. In enamines, the presence of a C=C double bond adjacent to the nitrogen atom leads to the delocalization of the lone pair.