对于折叠机催化阿尔多尔凝结的完整计算反应机制
Reilly Osadchey Brown1, Darren Demapan1, Qiang Cui1,2,3
1Department of Chemistry, Boston University, Boston, MA 02215.
ACS catalysis
|November 25, 2024
概括
合成的,称为折叠体,有效地催化阿尔多尔反应. 模拟揭示了折叠体中的氨基团如何驱动环闭,确定了设计改进催化剂的关键因素.
科学领域:
- * 有机化学 有机化学
- * 计算化学 计算机化学
- * 生物化学 * 生物化学
背景情况:
- * 折叠胺,来自α和β-氨基酸的合成,是碳-碳键形成阿尔多尔反应的有效催化剂.
- *它们的螺旋结构精确地对准了氨基群,使得合作催化成为可能,特别是在宏循环环闭合中.
- *现有的动力和质谱数据对详细的反应机制和速率决定步骤的洞察力有限.
研究的目的:
- * 阐明反应机制,并确定折叠剂催化阿尔多尔反应中的速度决定性步骤.
- * 调查氨基侧链身份对催化效率的影响.
- * 通过计算预测改进的折叠机催化剂设计.
主要方法:
- *采用了半经验密度的功能紧密结合量子力学/分子力学 (QM/MM) 的元动力学模拟.
- * 计算了环闭 aldol 反应中的 44 个基本步骤的自由能量和反应障碍.
- *分析了与氨基身份相关的趋势,并确定了关键中间体.
主要成果:
- * 对所有基本步骤计算了详细的自由能量概况和反应障碍.
- * 确定了特定的氨基侧链,这些氨基侧链显著影响反应速率.
- * 提供了对催化循环的机械见解,精确指出了速度限制的步骤.
结论:
- *计算机模拟提供了一种强大的方法来理解复杂的折叠机催化机制.
- * 氨基侧链标识对于优化 aldol 反应中的折叠分子催化剂性能至关重要.
- *根据模拟预测,预计拟议的折叠分子突变体将表现出增强的催化活性.
相关概念视频
01:10C–C Bond Formation: Aldol Condensation Overview
13.5K
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.
13.5K
01:08Base-Catalyzed Aldol Addition Reaction
3.2K
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.
3.2K
01:27Aldol Condensation with β-Diesters: Knoevenagel Condensation
3.0K
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.
3.0K
01:33Aldol Condensation vs Claisen Condensation
5.8K
Aldol condensation is an acid or base-catalyzed condensation between aldehydes or ketones to give an α,ꞵ-unsaturated carbonyl compound. A base-promoted condensation between ester molecules to produce a ꞵ-ketoester is known as the Claisen condensation. In the presence of a base, both reactions involve deprotonation of the acidic α hydrogen to produce the corresponding enolates. The nucleophilic enolates attack their respective nonenolized carbonyl compound forming a tetrahedral...
5.8K
00:57C–C Bond Cleavage: Retro-Aldol Reaction
5.5K
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.
5.5K
01:15Acid-Catalyzed Aldol Addition Reaction
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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.
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