Z-またはE-三置換型アリルアルコールとエーサーの合成 動力的に制御されたクロスメタテシスによるRu カテコチオラート複合体
Chaofan Xu1, Zhenxing Liu1, Sebastian Torker1
1Department of Chemistry, Merkert Chemistry Center, Boston College , Chestnut Hill, Massachusetts 02467, United States.
Journal of the American Chemical Society
|October 26, 2017
まとめ
この研究は,Z-またはE-三置換アルケンを生成するための最初の運動制御された交叉転移反応を導入する. ルテニウム触媒を用いて,この方法は高いステレオ同位体純度を持つアリルアルコールとエーテルを効率的に生成します.
科学分野:
- 有機化学
- キャタリシス
- ステレオ選択合成
背景:
- 交差転移反応はアルケンの合成に不可欠である.
- 三置換アルケンの形成におけるステレオ化学の制御は,依然として課題である.
研究 の 目的:
- Z-またはE-三置換アルケンのための最初の運動制御されたクロスメタテシス反応の開発.
- アリルアルコールとエーテルを合成する際に,高い収量とステレオ同位体純度を達成する.
主な方法:
- ルーテニウム (Ru) カテコチオラート複合体を触媒として使用した (≤6.0mol %).
- 交差メタテシスのために動力的に制御された条件を使用した.
- 機械学的な洞察のためのDFT (密度関数理論) 研究を行った.
主要な成果:
- Z-またはE-三置換アルケンの合成を達成した.
- トライスプスチューテッドアリルアルコールとエーテルを最大81%の収量で得ることができる.
- 高いステレオ同位体純度 (> 98%) を証明した.
- アルコール,アルデヒド,エポキシド,カルボキシル酸,またはアルケニル基を持つオレフィンを含む広範な基板の範囲を示した.
結論:
- 開発された方法は,ステレオ定義の三置換アルケンの新しい経路を提供します.
- 触媒システムは有機合成の効率と広範な適用性を提供します.
- メカニズム的な理解は,観察されたステレオ化学的制御と反応効率をサポートする.
関連する概念動画
[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
2.9K
The Claisen rearrangement is a [3,3] sigmatropic rearrangement of allyl vinyl ethers to unsaturated carbonyl compounds. The rearrangement is a concerted pericyclic reaction proceeding via a chair-like transition state.
2.9K
E2 Reaction: Stereochemistry and Regiochemistry
13.8K
Elimination reactions of alkyl halides can yield one or more alkenes depending on the specific regiochemical and stereochemical considerations. While the regiochemistry of the reaction governs the location of the double bond in the product, the stereochemical requirements often influence the geometry.
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major...
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major...
13.8K
Preparation of Epoxides
9.5K
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...
9.5K
Preparation of Alcohols via Substitution Reactions
7.5K
Overview
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group. The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2, depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl halides, and the...
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group. The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2, depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl halides, and the...
7.5K
E1 Reaction: Stereochemistry and Regiochemistry
11.9K
One of the critical aspects of the E1 reaction mechanism, as also observed in E2, is the regiochemistry, with multiple regioisomers obtained as products. In the example discussed, the presence of water as a weak base favors elimination over substitution to generate two alkenes. Given that alkenes’ stability increases with the number of alkyl groups across the double bond, typically, E1 reactions lead to the Zaitsev product, for this is more substituted and stable than the Hofmann product.
11.9K
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
13.0K
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.
13.0K


