从醇和烯/因中通过有氧氧化激素添加级联从醇和烯/因中获得功能化四水
Patrick Fries1, Daniel Halter, Alexander Kleinschek
1Fachbereich Chemie, Organische Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse, D-67663 Kaiserslautern, Germany.
Journal of the American Chemical Society
|February 26, 2011
概括
双醇的催化有氧氧化产生循环的激素. 这些基因被各种不和化合物捕获,通过立体选择性氧化-添加级联产生替代的四.
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:
- 双醇是有机合成中的多功能前体.
- 开发高效的合成替代四水的方法至关重要.
- 极端循环化反应为循环化合物提供了强大的途径.
研究的目的:
- 开发一种新的有氧氧氧化-添加级联,用于四二合成.
- 探索替代四水的立体选择性形成.
- 调查开发的方法论的范围和局限性.
主要方法:
- 使用 (II) 催化剂,对用和替代的4-醇进行有氧氧化.
- 通过复合体介导的激进循环化,在存在诸如γ-烯或循环赫萨-1,4-二烯之类的氧化剂.
- 用各种氨酸和氨酸捕捉循环基.
主要成果:
- 立体选择性形成四水甲基基.
- 通过各种迈克尔受体和基因成功地捕获了基因.
- 合成具有定义立体化学 (2,3-trans, 2,4-cis, 2,5-trans) 的二-和三替代四.
- 通过多步级联来制备二聚体纯净的比斯特拉.
结论:
- 开发的有氧氧化-添加级联为立体定义的四酸提供了一条有效的路线.
- 该方法适用于一系列基板,证明了其多功能性.
- 这种方法为构建复杂的异环基架提供了有价值的工具.
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.
Preparation of Aldehydes and Ketones from Alcohols, Alkenes, and Alkynes
Aldehydes and ketones are prepared from alcohols, alkenes, and alkynes via different reaction pathways. Alcohols are the most commonly used substrates for synthesizing aldehydes and ketones. The conversion of alcohol to aldehyde, which involves the oxidation process, depends on the class of the alcohol used and the strength of the oxidizing agent. For instance, primary alcohol will form an aldehyde when treated with a weak oxidizing agent; however, it gets over-oxidized to a carboxylic acid in...
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
Preparation of Alcohols via Addition Reactions
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
Radical Anti-Markovnikov Addition to Alkenes: Mechanism
The reaction of hydrogen bromide with alkenes in the presence of hydroperoxides or peroxides proceeds via anti-Markovnikov addition. The radical chain reaction comprises initiation, propagation, and termination steps.
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy radical...
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy radical...


