通过NCP针催化的基转移化:范围和机制
Yulei Wang1, Zhidao Huang1, Xuebing Leng1
1State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis , Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences , 345 Lingling Road , Shanghai 200032 , China.
Journal of the American Chemical Society
|March 9, 2018
概括
这项研究引入了一种新的催化剂,用于使用乙醇转移化. 催化剂表现出高效率和选择性,为化学合成提供了更环保的方法.
科学领域:
- 有机金属化学
- 催化剂
- 有机合成
背景情况:
- 转移化 (TH) 是一个关键的合成工具,但它对使用乙醇作为源的未激活的应用仍然具有挑战性.
- 开发高效和选择性的催化系统对于可持续的化学转化至关重要.
- 复合物在包括化在内的各种催化反应中表现有前途.
研究的目的:
- 开发使用乙醇转移未激活的第一个通用催化方法.
- 合成和表征一种新的NCP类型的皮复合物,用于这种转化.
- 研究已开发的催化系统的基质范围,化学选择性和机械路径.
主要方法:
- 合成一种新的基于素的NCP类型皮复合物, (BQ-NC^O P) IrHCl.
- 用各种未激活的和乙醇作为源的催化转移化反应.
- 动力学和机械学研究,包括使用C2D5OD的动力同位素效应 (KIE) 测量.
- 反应中间体和静止状态的分析.
主要成果:
- (BQ-NC^O P) Ir/EtOH系统有效地催化各种未激活的基,异基和内部基.
- 在和碳酸的存在下观察到高化学选择性.
- 机理学研究显示了单替代和多替代的不同路径,具有不同的催化剂休息状态和KIE.
- 乙醇脱被确定为决定速度的步骤,乙烯酸是唯一的副产品.
结论:
- 使用乙醇进行非活化的新型有效的催化系统已建立.
- 催化剂具有广泛的基质范围和出色的化学选择性,使其对有机合成具有价值.
- 根据基替代模式发现了基本的机制差异,为催化过程提供了洞察力.
更多相关视频
相关概念视频
02:45Acid-Catalyzed Hydration of Alkenes
17.5K
Alkenes react with water in the presence of an acid to form an alcohol. In the absence of acid, hydration of alkenes does not occur at a significant rate, and the acid is not consumed in the reaction. Therefore, alkene hydration is an acid-catalyzed reaction.
17.5K
02:13Reduction of Alkenes: Catalytic Hydrogenation
14.2K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
14.2K
02:35Acid-Catalyzed Dehydration of Alcohols to Alkenes
24.2K
In a dehydration reaction, a hydroxyl group in an alcohol is eliminated along with the hydrogen from an adjacent carbon. Here, the products are an alkene and a molecule of water. Dehydration of alcohols is generally achieved by heating in the presence of an acid catalyst. While the dehydration of primary alcohols requires high temperatures and acid concentrations, secondary and tertiary alcohols can lose a water molecule under relatively mild conditions.
24.2K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.9K
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...
3.9K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
9.1K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
9.1K
01:14Mechanisms of Heat Transfer
1.8K
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
1.8K