サイクロプロペネスにグリニャード反応剤を選択的に添加するための銅触媒法
1Brown Laboratories, Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
Journal of the American Chemical Society
|November 28, 2002
まとめ
銅で触媒化されたグリナード反応剤をサイクロプロペンに添加すると,キラル四次中心が形成されます. この方法は,優れたダイアステレオ選択性を持つ高度に機能化されたサイクロプロパンの合成を可能にします.
科学分野:
- 有機金属化学 有機金属化学
- オーガニック・シンセシス オーガニック・シンセシス
- ステレオ選択的反応
背景:
- サイクロプロペンは,独特の反応性を有するストレントサイクルアルケーンである.
- サイクロプロペンを機能化するステレオ選択的方法の開発は,複雑な分子合成に不可欠です.
- グリニャード反応剤は,有機化学における多用途の核愛素である.
研究 の 目的:
- サイクロプロペンにグリニャード反応剤を加えるための銅触媒法を開発する.
- 足し算反応のステレオ化学的結果を調査する.
- さらに機能化するために生成されたサイクロプロピルメタルの中間物質の有用性を調査する.
主な方法:
- 1-アルキル-3-ヒドロキシメチルcyclopropenesおよびそれらのMOMエーテルにGrignardの反応剤 (アルキル,アルケニル,アルキニルマグネシウムハリド) の銅触媒添加.
- 顕微鏡法を用いたダイアステレオ選択性の分析.
- 中間サイクロプロピルメタルの反応は,様々な電ophiles.
主要な成果:
- 添加は,サイクロプロペン環の既存の置換物と同期して発生します.
- グレニャード反応剤の幅広い範囲で優れたダイアステレオ選択性が達成されました.
- この反応は,キラルな全炭素四分中心を成功裏に生成します.
- サイクロプロピル金属の中間物質の後の反応により,高度に機能化されたサイクロプロパンが得られます.
結論:
- サイクロプロペンにグリニャード製のステレオセレクティブ添加剤を新たに効率的なCu誘導法が確立されました.
- この方法論は,価値あるキラル・サイクロプロパンの構成要素へのアクセスを提供します.
- 開発されたプロトコルは,複雑な有機分子を構築するための強力なツールを提供します.
関連する概念動画
Acid Halides to Ketones: Gilman Reagent
Lithium dialkyl cuprate, also known as Gilman reagents, selectively reduces acid halides to ketones. The acid chloride is treated with Gilman reagent at −78 °C in the presence of ether solution to produce a ketone in good yield.
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen double...
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen double...
Nitriles to Ketones: Grignard Reaction
Organomagnesium halides, commonly known as Grignard reagents, convert nitriles to ketones and proceed through a nucleophilic acyl substitution. Nitriles react with a Grignard reagent, followed by an aqueous acid, to yield ketones. The reaction introduces a new carbon–carbon bond. The alkyl–magnesium bond in the Grignard reagent is highly polar, so the alkyl carbon develops a carbanionic character and acts as a nucleophile.
The mechanism begins with a nucleophilic attack by the Grignard reagent...
The mechanism begins with a nucleophilic attack by the Grignard reagent...
Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
Acid Halides to Alcohols: Grignard Reaction
Organomagnesium halides, commonly known as Grignard reagents, convert acid halides to tertiary alcohols. The reaction requires two equivalents of the Grignard reagent and proceeds via a ketone intermediate.
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
Preparation of Carboxylic Acids: Carboxylation of Grignard Reagents
Carboxylic acids can be prepared by the carboxylation of Grignard reagents (RMgX). This method is convenient for converting alkyl (primary, secondary or tertiary), vinyl, benzyl, and aryl halides to carboxylic acids with one additional carbon than the starting RMgX.
Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.

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