区域选择性,催化性1,1-二化埃尼因
Zi-Xuan Wang1, Keith Livingstone1, Carla Hümpel1
1Institute for Organic Chemistry, Westfälische Wilhelms-Universität (WWU) Münster, Münster, Germany.
Nature chemistry
|October 16, 2023
概括
研究人员开发了一种使用催化剂的新方法,从中制造出有价值的二化分子. 这种方法简化了复杂化化合物的合成,为传统方法提供了多功能替代方案.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 化学 的化学
背景情况:
- 化小分子在各种应用中至关重要,但由于自然资源有限,它们的合成具有挑战性.
- (I) / (III) 催化为从易于获得的基底合成化化合物提供了一个有前途的途径.
- 现有的方法通常需要特定的基质,如 styrenes,限制更广泛的适用性.
研究的目的:
- 开发一种更具多功能性和操作简单的合成二化合物的方法.
- 探索用作为有效基质在催化化反应中的用法.
- 扩大有机催化二化范围,超越烯衍生物.
主要方法:
- 使用 (I) / (III) 催化剂来激活其他基质.
- 在现场生成的λ3-中使用,以促进化转换.
- 研究了反应机制,包括潜在的离子重组,类似于 styrene 反应.
主要成果:
- 成功证明,可以作为有能力的基质,类似于 styrenes,在催化二化中.
- 开发了一种简单的方法,用于从中合成具有高度多功能性的同质二化物.
- 通过30多个实例实现了广泛的基质范围,证明了高产率 (高达>90%) 和在目标合成中的适用性.
结论:
- enynes是催化二化有效和多功能基质,扩大了这种催化系统的实用性.
- 开发的方法提供了一个操作上简单和高效的途径,以获得有价值的同质二化物.
- 这种方法减轻了对基替代物的需求,为获得各种化分子提供了更具适应性的策略.
相关概念视频
01:33Regioselective Formation of Enolates
2.6K
As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are more stable. But the energy required to form kinetic enolates is less.
2.6K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
14.3K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
14.3K
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
01:14Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
2.5K
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
2.5K
02:43E1 Reaction: Stereochemistry and Regiochemistry
9.6K
One of the critical aspects of the E1 reaction mechanism, as also observed in E2, is the regiochemistry, with multiple regioisomers obtained as products. In the example discussed, the presence of water as a weak base favors elimination over substitution to generate two alkenes. Given that alkenes’ stability increases with the number of alkyl groups across the double bond, typically, E1 reactions lead to the Zaitsev product, for this is more substituted and stable than the Hofmann product.
9.6K
02:24Reduction 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