通过催化不对称的跨乙烯化,通过同类醇的动态分辨率
Ilija Čorić1, Steffen Müller, Benjamin List
1Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
Journal of the American Chemical Society
|November 20, 2010
概括
一种新的酸催化剂,STRIP,可以通过转化使 homoaldols 的高度 enantioselective 的动态分解. 这种方法有效地解决了二级和三级同类醇,并取得了很好的结果.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 不对称的合成方法
背景情况:
- 荷马阿尔多尔产品是有价值的合体构建块.
- 在有机化学中,对酶选择性合成的高效方法至关重要.
- 动力分辨率提供了一种途径,可以访问基丰富化合物.
研究的目的:
- 开发一种高分离选择性方法,用于同类醇的动态分离.
- 为了确定一个新型的催化剂的交换乙化反应.
- 为了证明开发的方法的广泛适用性.
主要方法:
- 基于螺旋环 1,1'-螺旋基因丹骨干的新型酸催化剂 (STRIP) 的设计和合成.
- 用STRIP催化剂在 homoaldols 的动力分辨率中通过 transacetalization 的应用.
- 对二级和三级同类醇的酶选择性和效率的分析.
主要成果:
- 实现了高分离性运动分辨率的homoaldols.
- 确定了STRIP作为交换乙化反应的优质催化剂.
- 对于二级和三级同类醇表现出了出色的结果,展示了催化剂的多功能性.
结论:
- 新型的STRIP酸催化剂对于homoaldols的enantioselective动力分解非常有效.
- 交换乙化反应提供了一条有效的途径,以致于以酶体丰富的homoaldols.
- 开发的方法为不对称合成提供了有价值的工具.
相关概念视频
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.
01:19Aldehydes and Ketones with Alcohols: Hemiacetal Formation
Similar to water, alcohols can add to the carbonyl carbon of the aldehydes and ketones. The addition of one molecule of alcohol to the carbonyl compound forms the hemiacetal or half acetal. As depicted below, in a hemiacetal, the carbon is directly linked to an OH and OR group.
01:27Aldol 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.
00:57C–C Bond Cleavage: Retro-Aldol Reaction
The reverse of the aldol addition reaction is called the retro-aldol reaction. Here, the carbon–carbon bond in the aldol product is cleaved under acidic or basic conditions to form two molecules of carbonyl compounds. The mechanism of the reaction consists of three steps.
In the first step, as depicted in Figure 1, the base deprotonates the β-hydroxy ketone at the hydroxyl group to form an alkoxide ion.
In the first step, as depicted in Figure 1, the base deprotonates the β-hydroxy ketone at the hydroxyl group to form an alkoxide ion.
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.