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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
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基底状態のN-C ((O) による原始アミドの可逆的歪曲 不安定化:高度に歪んだ回転逆のアシクリックアミド
Guangrong Meng1, Shicheng Shi1, Roger Lalancette1
1Department of Chemistry, Rutgers University , 73 Warren Street, Newark, New Jersey 07102, United States.
Journal of the American Chemical Society
|December 15, 2017
まとめ
研究者は,伝統的な平面アミド結合の概念を破って,最初のアサイクリック・トウィスト・アミドを作りました. この突破により アミドの逆転が可能になり 化学的設計と合成に影響を与えます
科学分野:
- 有機化学
- 構造化学
- 生物化学
背景:
- アミド結合は伝統的に平面性と考えられており,1930年代にポールリングによって確立された特徴である.
- アミド平面性は,様々な化学分野における反応性と化学特性に大きな影響を与える.
- アミドの平面性を制限するには,通常,アミドを硬い循環系に組み込む必要があります.
研究 の 目的:
- アサイクリック・トウィスト・アミドの第1種を報告する.
- 原始アミドからトウィストアミドを製造するための新しい,可逆的な方法を示す.
- 非平面性アミド結合の構造的,エネルギー的,および反応性の影響を調査する.
主な方法:
- 主要なアミド窒素原子のディテルト・ブトキシカルボニレーション
- 多種多様な電子的に変化した歪みアミドの合成と完全な構造的特徴づけ.
- アミド結合の変形と分裂を理解するための反応性研究と計算分析.
主要な成果:
- ほぼ垂直の回転を持つ最初のアサイクリック回転アミドの準備が成功しました.
- 特定の条件下で選択的な割れを含む,異常なアミド結合特性を示す.
- 計算研究によるアミド結合変形の詳細な構造とエネルギー評価.
結論:
- アサイクリック・トウィスト・アミドを生成するための新しい,可逆的な方法が開発されました.
- 歪んだアミドは独特の反応性を発揮し,化学合成の新たな可能性を提供します.
- この研究は,化学と生化学におけるアミド結合非平面性を操作するための新しいパラダイムを提供します.
関連する概念動画
01:07Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
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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.
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01:19Amines to Amides: Acylation of Amines
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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.
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01:26Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
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The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
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01:29Preparation of Amides
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Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
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