有機触媒カルボニル-オレフィンメタテシス
Allison K Griffith1, Christine M Vanos, Tristan H Lambert
1Department of Chemistry, Columbia University, New York, New York 10027, United States.
Journal of the American Chemical Society
|November 7, 2012
まとめ
アルデヒドとサイクロプロペンのリング開封のためのヒドラジン触媒を使用して,新しい触媒カルボニル-オレフィンメタテシス戦略が開発されました. このアプローチは [3 + 2] パラダイムを利用し,メタテシス化学における伝統的な [2 + 2] サイクロアディションモードを超越します.
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
- メタテシス反応 メタテシス反応
背景:
- 伝統的なメタテシスの戦略は,しばしば [2 + 2] のサイクル加法メカニズムに依存しています.
- オレフィンおよびカルボニル変換のための新しい触媒システムの開発は,合成効率にとって極めて重要です.
研究 の 目的:
- 新しい触媒カルボニル-オレフィンメタテシス戦略について報告する.
- アルデヒドとサイクロプロペンのリング開きメタテシスを調査する.
- メタテシス化学のための新しい [3 + 2] パラダイムを導入する.
主な方法:
- 単純なヒドラジン触媒を用いたものです.
- サイクロプロペンのリング開きメタテシスを用いる.
- サイクロプロペンがアルデヒドと反応する.
主要な成果:
- 触媒カルボニル-オレフィンメタテシスの開発に成功.
- ハイドラジン触媒を用いた反応の実証.
- [3 + 2]反応経路の確立.
結論:
- 報告された戦略は,カルボニル-オレフィンメタテシスの新しい経路を提供します.
- ハイドラジン触媒反応は,従来のメタテシスメカニズムに代替手段を提供している.
- [3 + 2] パラダイムは,メタテシス化学における重要な概念的進歩を表しています.
関連する概念動画
01:13Olefin Metathesis Polymerization: Overview
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
03:00Preparation 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...
03:08Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
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.