在室温下发生催化 2-arylation 的内醇
Nicholas R Deprez1, Dipannita Kalyani, Andrew Krause
1Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, USA.
Journal of the American Chemical Society
|April 13, 2006
概括
研究人员开发了一种新的催化方法,用于使用 (III) 试剂进行直接的醇化. 这种高效的工艺在温和的条件下工作,使得各种烯和烯的合成成为可能.
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:
- 催化交叉合反应是有机合成的基础.
- 与传统方法相比,异循环的直接结合提供了一种更为原子经济的方法.
- 开发适度和高效的催化系统,以实现内醇功能化,仍然是活跃的研究领域.
研究的目的:
- 开发一种新的 ((II) 催化方法,用于直接2 - 化.
- 为了利用高价 (III) 化试剂进行这种转化.
- 为了在温和的条件下实现反应,包括环境空气和水分.
主要方法:
- 采用 ((II) 催化剂,用于直接化.
- 使用diaryliodonium tetrafluoroborate ([Ar-I-Ar]BF4) 作为一个结合剂.
- 研究反应机制,可能涉及 (II) / (IV) 催化循环.
主要成果:
- 通过使用开发的Pd催化方法,成功地实现了醇的直接2-化.
- 在温和条件下 (室温,空气,湿度) 反应有效地进行.
- 合成了多种多样的2 - 化醇和醇,证明了该方法的广泛适用性.
- 确定了 (III) 试剂的现场生成程序,提高了实用性.
结论:
- 已经建立了一种新且高效的Pd(II) 催化方法,用于直接对内醇进行2 - 化.
- 反应的温和条件和对空气/水分的耐受性归因于拟议的Pd (II) /Pd (IV) 催化循环.
- 这种方法为合成多种多样化的2 - 化醇和醇提供了一种有价值的工具.
相关概念视频
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
02:40Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration
Introduction
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
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.
01:12Acid Halides to Esters: Alcoholysis
Alcoholysis is a nucleophilic acyl substitution reaction in which an alcohol functions as a nucleophile. Acid halides react with alcohol to produce esters. The mechanism proceeds in three steps:
01:21Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
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...
01:01Ketones with Nonenolizable Aromatic Aldehydes: Claisen–Schmidt Condensation
Benzaldehyde, like formaldehyde, lacks an α hydrogen and cannot enolize to form an enolate. Hence, the reaction of benzaldehyde with a ketone in the presence of an aqueous base forms a single crossed product. This reaction is referred to as Claisen–Schmidt condensation.
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt condensation is...
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt condensation is...