末端アルキンおよびその合成ユーティリティの代替エノール誘導体の調製
John R DeBergh1, Kathleen M Spivey, Joseph M Ready
1Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9038, USA.
Journal of the American Chemical Society
|June 4, 2008
まとめ
この研究では,ターミナルアルキンから,タンデムカルボメタレーション/酸素化プロセスを用いてステレオ定義エノール誘導体を生成するための新しい方法が紹介されています. この多用途な反応は,複雑な分子構造のための貴重な中間物質の合成を可能にします.
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:
- ターミナルアルキンは,有機合成における汎用的な構成要素である.
- エノール誘導体のステレオセレクティブ合成は,複雑な分子を構築するために重要です.
研究 の 目的:
- 末端アルキンからステレオ定義エノール誘導体を製造するための新しい方法を開発する.
- 価値ある有機化合物の合成におけるこの方法の有用性を実証する.
主な方法:
- 終末アルキンのCp2ZrCl2触媒メチル発光.
- ヴィニラランをペロキシジンク種で酸化して,三置換エノラートを形成する.
- エノラートをカルボキシルアンヒドリドまたはシリルトリフラートで電離的に捕まえる.
主要な成果:
- ステレオ定義の三置換エノールエステルとシルアンの合成が成功しました.
- アルコール,ヘテロサイクル,オレフィン,ニトリルを含む様々な機能群に対する耐性が実証されています.
- 昆虫フェロモンフロントアリンをエナンチオセレクティブで合成する応用.
- アルファ-ヒドロキシアルデヒドをホモロゲーション,還元性アミネーション,酸化,オレフィネーションによる有価な製品に変換する.
結論:
- 開発されたタンデムカルボメタライゼーション/酸素化戦略は,ステレオ定義のエノール誘導体への効率的なアクセスを提供します.
- この方法論は,複雑な有機分子と自然製品の合成のための強力なツールを提供します.
- タンデムカルボメタライゼーション/アミネーション反応のさらなる探求は,エネ-ヒドラジン合成の有望性を示しています.
関連する概念動画
02:27Preparation of Alkynes: Alkylation Reaction
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
01:26Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
α-Substituted ketones or aldehydes can be synthesized from enamines by the Stork enamine reaction, named after its pioneer Gilbert Stork. Enamines are useful synthetic intermediates where the lone pair on nitrogen is in conjugation with the C=C bond. They resemble enolate ions, as the resonance forms of both species have a nucleophilic α carbon.
02:34Preparation of Alkynes: Dehydrohalogenation
Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
01:33Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes
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01:07Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
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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.