催化cyclization/carboalkoxylation的阿尔基尼尔内醇的帕拉催化循环化/碳氧化
1P. M. Gross Chemical Laboratory, Duke University, Durham, NC 27708-0346, USA.
Journal of the American Chemical Society
|August 19, 2004
概括
这项研究引入了一种新的催化反应,用于合成四碳醇. 高效的循环化/碳氧化方法在温和条件下工作,并耐受各种功能组.
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:
- 印醇衍生物是天然产品和药品中重要的结构动图.
- 有效的合成途径,以替代碳醇是高度寻求的.
- 催化反应为C-C和C-原子键形成提供了强大的工具.
研究的目的:
- 开发一种新的催化方法,用于合成四碳酸.
- 为了研究循环化/碳氧化反应的范围和局限性.
- 为了探索这种方法对各种内醇基质的实用性.
主要方法:
- 在二氧化碳大气下,甲醇中的2 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 的反应与催化PdCl2 - - - - - - - - - - - - - - - - - - - - - - - - - CH3CN) 2和石化CuCl2发生反应.
- 反应条件的优化,包括催化剂负荷,温度和反应时间.
- 基质范围的分析,包括基链长度和替代模式的变化.
主要成果:
- 一个四碳醇衍生物的成功合成,在83%的产量中作为单个区域异构体.
- 催化循环化/碳氧化证明了对基链上的替代物的耐受性.
- 这种反应对各种醇衍生物有效,包括具有不同基链长度和附着位置的基衍生物.
结论:
- 已经建立了一种新且高效的催化循环/碳氧化反应,用于四碳醇合成.
- 该方法具有多功能性,可以容忍一系列的功能组和基质变化.
- 这为访问复杂的含醇分子提供了一个有价值的新工具.
相关概念视频
Alkynes 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.
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
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.
Reactions of Aldehydes and Ketones: Baeyer–Villiger Oxidation
Baeyer–Villiger oxidation converts aldehydes to carboxylic acids and ketones to esters. The reaction uses peroxy acids or peracids and is often catalyzed by acid. The reaction is named after its pioneers, Adolf von Baeyer and Victor Villiger. The reaction is achieved by a wide range of peracids such as m-chloroperoxybenzoic acid (mCPBA), perbenzoic acid (C6H5COOOH), peracetic acid (CH3COOOH), hydrogen peroxide (H2O2), and tert-butyl hydroperoxide (t-BuOOH).
The carbonyl center is activated by...
The carbonyl center is activated by...
Acid-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...
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
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.
Acid-Catalyzed Aldol Addition Reaction
The aldol reaction of a ketone under acidic conditions successfully forms an unsaturated carbonyl as the final product instead of an aldol. The acid-catalyzed aldol reaction is depicted in Figure 1.


