シリルビニルエーテルを (アルファダイミン) PdR+によるオレフィンとの共ポリマー化
1Department of Chemistry, The University of Chicago, Illinois 60637, USA.
Journal of the American Chemical Society
|September 14, 2006
まとめ
この研究は,パラジウム触媒がオレフィンとシリルビニルエーテルを共聚体化できることを示しています. その結果生成されるコポリマーを脱塩して,貴重なビニアルコールのコポリマーが得られます.
科学分野:
- 有機金属化学 有機金属化学
- ポリマーサイエンスの科学
- カタリシス カタリシス カタリシス
背景:
- オレフィンポリメリゼーションは,ポリマー化学の礎石です.
- 多様なモノマーをポリマーチェーンに組み込むことは,依然として課題です.
- シリルビニルエーサーは,ポリマー改変のためのユニークな機能を提供します.
研究 の 目的:
- パラジウム触媒を用いてオレフィンとシリルビニルエーサーの共聚合を調査する.
- この新しい共聚合反応のメカニズムを解明するために.
- 結果となるコポリマーによるさらなる機能化の可能性を調査する.
主な方法:
- コポリメリゼーション反応に (アルファ-ジミン) PdMe+ 触媒を使用した.
- モノマーとして様々なシリルビニルエーテルと1-ヘクセンを使用した.
- 分析されたポリマー構造は,光譜技術を用いて分析した.
- 代替メカニズムを排除するために制御実験を行った.
主要な成果:
- 1-ヘクセンのシリルビニルエーテル (R=tBu,SiMe3) との共ポリマー化が成功しました.
- 挿入/連鎖歩行メカニズムを提案し,カチオンの経路や根幹経路とは異なる.
- コポリマーを脱塩させ,ビニールアルコールコポリマーを生成することを実証した.
- コポリマー構造における主要なコモノマー組み込みパターンを特定した.
結論:
- (アルファダイミン) PdMe+触媒は,オレフィンとシリルビニルエーテルの共聚合を効果的に媒介する.
- 提案された挿入/チェーンウォーキングメカニズムは,反応経路の洞察を提供します.
- 結果となるコポリマーの脱塩化は,機能的なポリ (オレフィン・コ・ビニールアルコール) 材料への経路を提供します.
関連する概念動画
Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
Preparation of Acid Anhydrides
One of the methods for preparing symmetrical or unsymmetrical acid anhydrides involves the treatment of acid chlorides with the sodium salt of carboxylic acids. The reaction proceeds via a nucleophilic acyl substitution.
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
The carboxylate ion acts as a nucleophile that attacks the carbonyl carbon of the acid chloride to form a tetrahedral intermediate. Subsequently, the re-formation of the carbonyl group with the loss of the chloride ion as a leaving group leads to the formation of an acid...
α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
The method to achieve α-brominated carboxylic acids using a mixture of phosphorus tribromide and bromine is known as the Hell–Volhard–Zelinski reaction. The reaction is catalyzed by phosphorus tribromide, which can be used directly or produced in situ from red phosphorus and bromine. The mechanism comprises PBr3 catalyzed conversion of acid to acid bromide and hydrogen bromide. The acid bromide enolizes to its enol form in the presence of HBr. The nucleophilic enol attacks the bromine molecule...
Vicinal Diols via Reductive Coupling of Aldehydes or Ketones: Pinacol Coupling Overview
Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of aldehydes or ketones in the presence of hydrocarbon solvent to yield vicinal diols.
Alkenes 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.
Cationic Chain-Growth Polymerization: Mechanism
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the generated carbocation,...
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)

