没有过渡金属的可见光光电还原催化远程C-H化,由1,5-原子转移启用
Beiqi Sun1,2, Wenke Li2, Qianyi Liu2
1School of Materials Science and Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China.
Communications chemistry
|July 24, 2023
概括
我们开发了一种新的不含过渡金属的方法,用于使用光氧化催化剂进行C-H键玻利化. 这种方法可以通过原子转移 (HAT) 实现非反应性碳-键的功能化,以创建有价值的化学构件.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 合成方法论 合成方法论
背景情况:
- 碳- (C-H) 键的玻里化对于从原料化学品中合成多功能化学构件至关重要.
- 现有的方法通常需要过渡金属或恶劣的条件,限制了它们的适用性.
- 在有机合成中,开发高效且无金属的C-H玻利化策略仍然是一个重大挑战.
研究的目的:
- 建立一个新型的无过渡金属协议,用于光氧催化非激活的C ((sp3) -H键的玻利化.
- 为了证明由基激素启动的1,5-原子转移 (HAT) 对于远程C-H功能化的实用性.
- 提供适用于各种基质类型和功能组的多功能方法.
主要方法:
- 使用可见光的光雷多克斯催化,从酸衍生物中产生氨基基基.
- 1,5-原子转移 (HAT) 是指导化向远程C(sp3) -H键的关键步骤.
- 激进的时钟实验和密度函数理论 (DFT) 计算用于机械阐明.
主要成果:
- 成功过渡无金属光反氧催化化初级,二级和三级C ((sp3) -H键.
- 中等到良好的产品产量 (高达92%),具有广泛的功能组耐受性.
- 详细的机制性见解证实了由基激素启动的1,5-HAT通路.
结论:
- 开发了一种新且高效的方法,用于远程玻里化未激活的C(sp3) -H键.
- 无过渡金属光氧催化方法为合成有价值的有机构件提供了一种可持续和多功能替代方案.
- 这些发现提供了更深入地了解激素介导的C-H功能化中的HAT机制.
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
相关概念视频
02:36Regioselectivity and Stereochemistry of Hydroboration
8.2K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.2K
03:08Hydroboration-Oxidation of Alkenes
8.4K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.4K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
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...
3.4K
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
1.8K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
1.8K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.3K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
18.3K
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
8.7K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
8.7K