两种不同类型的化物的催化选择性转化为交叉合的
Yoichi Hoshimoto1, Masato Ohashi, Sensuke Ogoshi
1Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
Journal of the American Chemical Society
|March 17, 2011
概括
一种新的催化反应使得阿利法和阿里尔化物的选择性交叉合成为单一的. 这种100%原子效率的工艺不产生任何废物,同时表现出双化物对Ni的同时协调.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 绿色化学 绿色化学
背景情况:
- 从化物中选择性合成 Ester 在有机化学中至关重要.
- 传统的方法通常涉及多个步骤,并产生大量的废物.
- 开发用于化物交叉合的原子效率高的催化系统仍然是一个挑战.
研究的目的:
- 开发一种新型的催化方法,用于选择性合成来自亚利法和亚利尔化物等等分子混合物的交叉合.
- 调查所开发的反应的范围和效率.
- 阐明反应机制,重点关注Ni(0) /NHC催化剂的作用.
主要方法:
- 使用了Ni(0) /N-异环碳素 (NHC) 催化剂系统.
- 使用各种异质 (初级,二级,循环二级,三级) 和甲基的等质混合物.
- 进行了机理学研究,以探测化物对Ni(0) 中心的协调行为.
主要成果:
- 从混合的化物原料中获得单个交叉合的产品的选择性形成.
- 在多种不同的阿利法和阿里尔化物组合中证明了广泛适用性.
- 反应显示了100%的原子效率,并且没有产生化学废物.
- 机械研究表明,两个化物与Ni(0) 催化剂的同时协调是关键特征.
结论:
- 开发的Ni(0) /NHC催化反应提供了一种高效和选择性的途径,用于从化物合成交叉合.
- 该方法与绿色化学原则保持一致,因为它具有高原子经济性和零废物产生.
- 独特的同时双化协调机制为催化转换提供了新的见解.
相关概念视频
β-Dicarbonyl Compounds via Crossed Claisen Condensations
Crossed Claisen condensations are base-promoted reactions between two different ester molecules producing β-dicarbonyl compounds. The reaction involving esters, with both containing α hydrogen, results in a mixture of four different products that are difficult to isolate. This reduces the synthetic utility of the reaction.
Crossed Aldol Reactions: Overview
Crossed aldol addition is the reaction between two different carbonyl compounds under acidic or basic conditions. Here, both the carbonyl compounds function as nucleophiles and electrophiles. As shown in Figure 1, such a reaction yields a mixture of products, two of which are formed via self-condensation, while the remaining two are formed via crossed-condensation. Without adjustment, the reaction's usefulness in organic chemistry is decreased.
α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
The pinacol and McMurry reactions involve the reductive coupling of ketones or aldehydes. Similarly, the bimolecular reductive coupling of two ester molecules in the presence of sodium metal in an aprotic solvent yields an α-hydroxy ketone product. The α-hydroxy ketone is also called acyloin, so the reaction is referred to as ‘acyloin condensation.’
Crossed Aldol Reaction Using Strong Bases: Directed Aldol Reaction
The reaction between two different carbonyl compounds comprising α hydrogen in the presence of a strong base like lithium diisopropylamide (LDA) to form a crossed aldol product is known as a directed aldol reaction. The directed aldol reaction is depicted in Figure 1.
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
Aldol Condensation with β-Diesters: Knoevenagel Condensation
The Knoevenagel condensation is an aldol-type reaction involving the condensation of aldehydes or ketones with active methylene compounds such as β-diesters to produce substituted olefins.


