カチオン酸鉄 (III) ポルフィリン触媒による [4 + 2] サイクロアディションで,活性化されていないアルデヒドを単純なダイエンで加えた
Kyohei Fujiwara1, Takuya Kurahashi, Seijiro Matsubara
1Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
Journal of the American Chemical Society
|March 20, 2012
まとめ
カチオン性鉄 (III) ポルフィリン触媒は,アルデヒドとダイエンの間の効率的なヘテロ-ダイエルス-アルダー反応を可能にします. この強固な触媒は,高機能群耐性を示し,活性化されていないケトンと水の存在下でも動作します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 有機金属化学 有機金属化学
背景:
- ヘテロ-ダイエルス-アルダー反応は,複雑な有機分子を合成するための貴重なツールです.
- この反応のための効率的で選択的な触媒の開発は,合成化学にとって極めて重要です.
- 伝統的な方法は,しばしば活性化基板または厳しい条件を必要とします.
研究 の 目的:
- ヘテロ-ディエルス-アルダー反応におけるカチオン性鉄 (III) ポーフィリンの触媒的活性を調べる.
- 鉄触媒の化学選択性と機能群耐性を実証する.
- 温和で困難な条件下での触媒の有用性を探求する.
主な方法:
- カチオン酸鉄 (((III) ポルフィリンを触媒として利用した.
- サイクル添加反応では,アルデヒドと1,3-ディエンの範囲を使用した.
- 触媒の性能を非活性化ケトンと水性媒体でテストした.
主要な成果:
- 化学選択性の高いヘテロ・ディエルス・アルダー反応を達成した.
- 電子欠乏アルデヒドや活性ダイエンを必要とせずに,実証された触媒効率.
- 高い機能群耐性と触媒の強度を示した.
- 水と非活性化ケトンとの間にサイクル添加を成功裏に実行した.
結論:
- 酸性鉄 ((III) ポルフィリンは,ヘテロ-ダイエルス-アルダー反応の効果的な触媒である.
- 触媒は,有機合成のための多用途で堅牢な方法を提供します.
- この触媒システムは,適用可能な基板と反応条件の範囲を拡大します.
関連する概念動画
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[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.
01:16Cycloaddition 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.
02:04Oxidation 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.
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
01:27Cyclohexenones 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).
01:22Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.