通过它们的功能差异化,在亚利法性化物之间进行有效的有机催化交叉-阿尔多尔反应
Taichi Kano1, Hisashi Sugimoto, Keiji Maruoka
1Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Journal of the American Chemical Society
|October 18, 2011
概括
一种新的非对称的直接交叉阿尔多尔反应,可以精确控制合成复杂分子中的立体化学. 这种方法有效地使用性催化剂创建特定的抗或syn-aldol附加物.
科学领域:
- 有机化学 有机化学
- 不对称的合成方法
- 催化剂是一种催化剂.
背景情况:
- 阿尔多尔反应是有机合成中形成碳-碳键的基本反应.
- 在交叉阿尔多尔反应中达到高水平的化疗,立体和异体选择性仍然是一个重大挑战.
- 与传统方法相比,直接不对称的阿尔多尔交叉反应提供了更有效的途径来获得复杂的阿尔多尔添加物.
研究的目的:
- 开发一种化学和立体选择性不对称的直接交叉阿尔多尔反应.
- 为了在阿利法性化物和α-chloroaldehydes之间形成交叉阿尔多尔添加物时实现对和异 stereo 控制.
- 为了证明能够选择性地获得抗或syn-aldol adducts的能力.
主要方法:
- 使用普罗林作为一种有机催化剂.
- 使用一种新型的轴性性氨基硫胺作为催化剂.
- 研究阿利法性化物和α-化之间的反应.
主要成果:
- 开发的方法完全构成交叉阿尔多尔引证.
- 实现了高水平的异构选择性和异构选择性.
- 通过明智地选择催化剂,通过良好的到优秀的立体选择性获得了反-和syn-aldol adducts.
结论:
- 已经建立了一个多功能和高度选择性的非对称的直接交叉阿尔多尔反应.
- 使用普罗林或一种新型性氨基硫胺催化剂,可以对特定的阿尔多添加物进行受控合成.
- 这种方法为有价值的有机化合物的立体选择性合成提供了一个强大的工具.
相关概念视频
01:04Crossed 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.
00:56Crossed 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.
01:10C–C Bond Formation: Aldol Condensation Overview
Aldol condensation is an important route in synthetic organic chemistry used to generate a new carbon–carbon bond under basic or acidic conditions. The aldol condensation reaction presented in Figure 1 constitutes an aldol addition reaction followed by the dehydration process.
01:14Crossed Aldol Reaction Using Weak Bases
This lesson deals with the crossed aldol reaction using weak bases. The self-condensation of an aldehyde having α hydrogen is prevented by adding it slowly to a mixture of formaldehyde and weak bases like hydroxide and alkoxide. Upon slow addition of the aldehyde, the base deprotonates the α carbon of the aldehyde to form the corresponding enolate. The enolate subsequently attacks the formaldehyde to form a single crossed product. Figure 1 depicts the aforementioned reaction.
01:08Base-Catalyzed Aldol Addition Reaction
As depicted in Figure 1, base-catalyzed aldol addition involves adding two carbonyl compounds in aqueous sodium hydroxide to form a β-hydroxy carbonyl compound.
01:15Acid-Catalyzed Aldol Addition Reaction
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.