ZrCl4-キラルリン酸複合体による触媒非対称可視光デメイオ反応
Wenzhao Zhang1, Long Zhang1, Sanzhong Luo1
1Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, China, 100084.
Journal of the American Chemical Society
|June 21, 2023
まとめ
可視光はキラルジルコニウム触媒を用いた最初の非対称デ・メイオ反応を可能にします. この方法は,主要な中間物質が特定され,様々な基板に高い収穫量とエナチオ選択性を提供します.
科学分野:
- 有機化学
- 非対称な触媒
- 写真化学
背景:
- デ・メイオ反応は複雑な分子構造を 構築するための貴重なツールです
- 可視光のような穏やかな条件下で非対称な変種を開発することは,合成化学における重要な課題です.
研究 の 目的:
- 可視光照射下での最初の触媒非対称デ・メイオ反応を 達成する
- この変換のための新しい非対称バイナリ酸触媒 (ABC) システムを開発する.
主な方法:
- ジルコニウム塩化物とキラルリン酸 (CPA) を含む触媒システムを使用した.
- 反応を誘導するエネルギー源として可視光を使う.
- 提案されたキラルジルコニウムエノラート中間物質を分離し,特徴づけました.
主要な成果:
- 可視光下での触媒非対称デ・メイオ反応を成功裏に実証した.
- 1,3-ジケトンとアルケンの幅広い範囲で優れた収量 (> 99%) と高いエナチオ選択性 (最大 98% ee) を達成した.
- 主要なキラルジルコニウムエノラートに対する構造的証拠を提供し,反応の立体化学的結果を説明した.
結論:
- 開発された非対称バイナリー酸触媒 (ABC) システムは非対称デ・メイオ反応に対して非常に有効である.
- 可視光光レドックス触媒とキラルルイス酸触媒は,エナチオセレクティブ合成のための強力な戦略を提供します.
- この研究は,非対称なデ・メイオ反応の新しい基準を確立し,新しい合成方法論への道を開く.
関連する概念動画
α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
3.1K
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...
3.1K
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.4K
Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
7.9K
The Wittig reaction is the conversion of carbonyl compounds-aldehydes and ketones-to alkenes using phosphorus ylides, or the Wittig reagent. The reaction was pioneered by Prof. Georg Wittig, for which he was awarded the Nobel Prize in Chemistry.
7.9K
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
3.6K
The Wittig reaction, which converts aldehydes or ketones to alkenes using phosphorus ylides, proceeds through a nucleophilic addition‒elimination process.
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
3.6K
[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
2.2K
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.
2.2K
Sharpless Epoxidation
4.1K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
4.1K
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)

