タンデム マイケル添加/イリドエポキシデーションで,高度に機能化されたサイクロヘクサディエンエポキシド誘導体の合成を行う
Qing-Gang Wang1, Xian-Ming Deng, Ben-Hu Zhu
1State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, 354 FengLin Lu, Shanghai 200032, China.
Journal of the American Chemical Society
|April 2, 2008
まとめ
研究者らは,複雑なサイクロヘクサディエンエポキシド誘導体を合成するための新しい方法を開発した. この効率的なプロセスは,キラル触媒とのタンドムミハエル添加/エポキシデーションを使用し,高いエナチオセレクティビティを達成します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- アシンメトリック・シンセシス
背景:
- サイクロヘクサジエネエポキシドは,貴重な合成中間物質である.
- 合成のためのステレオ選択的方法の開発は,挑戦的です.
研究 の 目的:
- サイクロヘキサジネエポキシド誘導体の高効率でダイアステロ選択的合成を開発する.
- マルチステレオセンター化合物の合成において高いエナンチオセレクティビティを達成するために.
主な方法:
- タンデム・イライド・マイケルの加法とエポキシデーションが用いられました.
- キラル硫イリドは,主要な反応剤として使用されました.
主要な成果:
- 開発された方法は,サイクロヘクサジエネエポキシド誘導体への効率的なアクセスを提供します.
- 反応において高いダイアステレオ選択性が観察された.
- エナチオセレクティビティは96%のエナチオメール過剰 (ee) まで達成されました.
結論:
- タンデムミハエル添加/エポキシデーションは,複雑なサイクロヘキサジネエポキシドを合成するための強力な戦略です.
- キラルシルフォニウムイライドの使用は,高いレベルのステレオ制御を可能にします.
関連する概念動画
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
Conjugate Addition of Enolates: Michael Addition
The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.
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.
Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.


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