一种有机光催化可见光驱动的多组分方法,用于通过C(sp3) -H键功能的激活基的碳亚基/化
Debabrata Das1, Krishna Gopal Ghosh1, Sumit Garai1
1Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, West Bengal, India. suresh@iiserkol.ac.in.
Organic & biomolecular chemistry
|September 11, 2023
概括
这项研究提出了一种绿色,无金属的方法,用于使用可见光对基的碳硫化. 在温和的条件下,有机光催化反应有效地形成新的碳-碳和碳-硫键.
科学领域:
- 有机化学 有机化学
- 光催化作用的光催化
- 绿色化学 绿色化学
背景情况:
- 可见光光催化剂为传统合成方法提供了一个可持续的替代方案.
- 多组分反应 (MCR) 能够在单个步骤中高效地构建复杂分子.
- 碳硫化反应对于合成含硫有机化合物至关重要.
研究的目的:
- 开发一种新的可见光驱动的有机光催化多组分方法,用于激活基的碳化.
- 为了在环境良好的条件下实现直接的C(sp3) -H功能化,然后通过电友性基/基乙烯化.
- 建立一个没有过渡金属和过氧化物的协议,以有效地形成C-C和C-S键.
主要方法:
- 可见光辐射. 可见光辐射.
- 使用pyrylium盐进行器官光催化.
- 多元组件反应涉及激活基,C ((sp3) -H来源和硫醇.
- 无氧化解和无过渡金属的条件.
主要成果:
- 通过直接的C ((sp3) -H功能化和随后的醇添加,成功地进行了活性基的碳硫化.
- 在一个中形成两个新的C(sp3) -C(sp3) 和C(sp3) -S债券.
- 在广泛的基质中表现出优异的功能群耐受性和化学选择性.
- 实现了可扩展性和利用自然阳光,突出了协议的能源效率和可持续性.
结论:
- 开发的有机光催化方法提供了一种高效的,绿色的,可扩展的碳素化方法.
- 这种没有过渡金属和过氧化物的协议为合成有价值的含硫有机分子提供了可持续的替代方案.
- 使用廉价,易于获得的试剂和自然阳光增强了该方法的实用性和环保性.
相关概念视频
Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.1K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.1K
Photochemical Electrocyclic Reactions: Stereochemistry
1.9K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.9K
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.2K
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.
18.2K
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.8K
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.
7.8K
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
3.8K
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
3.8K
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
1.9K
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.
1.9K


