催化剂控制的定向组转位在3 - 碳胺英多尔和金属碳化合物的选择性C-H功能化位点
Kuang Gu1, Mary T Hall1, Zachary D Tucker1
1Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.
Nature communications
|January 2, 2025
概括
这项研究提出了一种使用催化剂控制的新方法来功能化. 催化剂促进基迁移和C-H功能化,而催化剂产生具有高选择性的C2-功能化.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 异环化学 异环化学
背景情况:
- 在药物化学中,醇和氧醇框架至关重要.
- 选择性C-H功能化是有机合成的一个关键挑战.
- 开发替代的策略,以 heteroaryl C-H 功能化是很重要的.
研究的目的:
- 开发催化剂控制的,选择性地点的C-H功能化3 - 乙性内醇.
- 探索使用胺基导向组用于CH激活和功能化.
- 研究Rh (I) /Ag (I) 和Ir (III) /Ag (I) 催化系统的不同反应模式.
主要方法:
- 使用Rh (I) /Ag (I) 联合催化剂进行C-H激活和1,2-转位.
- 使用Ir (III) /Ag (I) 联合催化剂来实现C2功能化.
- 通过实验研究研究机械路径.
主要成果:
- 通过1,2-转位和C-H功能化,Rh (I) /Ag (I) 催化剂产生交叉合的附加物.
- 催化剂选择性地产生了C2功能化醇,绕过了基迁移.
- 两种催化剂系统都实现了异常的位点选择性,仅形成C-H功能化的内醇.
结论:
- 氨基基导向组使3 - 乙基醇的多功能C-H功能化成为可能.
- 催化剂的选择决定了反应路径,导致了转位或直接的C2功能化.
- 这些发现提供了一种强大而有选择的方法来研究醇和醇衍生物.
相关概念视频
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
5.6K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the...
5.6K
01:09Directing Effect of Substituents: meta-Directing Groups
4.2K
Substituents on the benzene ring that direct an incoming electrophile to undergo substitution at the meta position are called meta directors. All meta directors either have a positive charge on the atom directly bonded to the ring or a partial positive charge. These groups function by withdrawing electrons from the ring through inductive and resonance effects. Consider the carbocation intermediates formed upon the addition of an electrophile on nitrobenzene at the...
4.2K
01:13meta-Directing Deactivators: –NO2, –CN, –CHO, –CO2R, –COR, –CO2H
5.2K
All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...
5.2K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.2K
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...
3.2K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.0K
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...
8.0K
01:14Directing Effect of Substituents: ortho–para-Directing Groups
6.0K
Ortho–para directors are substituent groups attached to the benzene ring and direct the addition of an electrophile to the positions ortho or para to the substituent. All electron-donating groups are considered ortho–para directors. They donate electrons to the ring and make the ring more electron-rich. The ring is therefore susceptible to the addition of electrophiles. Substituents such as amino, hydroxy, or alkoxy, containing lone pairs on the atom adjacent to the ring, donate...
6.0K