合醇作为激进合剂剂. 和的整体油脂化
Nicolas Charrier1, Béatrice Quiclet-Sire, Samir Z Zard
1Laboratoire de Synthèse Organique, CNRS UMR 7652, Ecole Polytechnique, 91128 Palaiseau, France.
Journal of the American Chemical Society
|June 19, 2008
概括
2 - 基基基醇与酸盐反应,产生具有高立体选择性的基. 这一过程提供了一种新的合成途径,类似于维蒂格精,用于创建复杂的有机分子.
科学领域:
- 有机化学 有机化学
- 合成方法论 合成方法论
- 化学 的化学
背景情况:
- 醇是多用途的合成中间体.
- 化反应对于C=C键的形成至关重要.
- 化衍生物具有独特的电子性质.
研究的目的:
- 为了探索2 - 基基合醇的反应性.
- 开发一种新的立体选择性精制法.
- 为了建立一个合成相当于维蒂格反应.
主要方法:
- 2 - - 氧基合醇与酸盐的反应.
- 使用劳洛过氧化物进行激进启动.
- 对基产物的立体化学分析.
主要成果:
- 从反应中形成基.
- 在许多情况下观察到高立体选择性.
- 从化物/质开始时,证明该过程作为维蒂格化等价物.
结论:
- 描述的反应提供了一个有效的途径,以立体定义的基.
- 这种方法扩大了有机合成的工具包.
- 2-甲基组影响反应性和立体选择性.
相关概念视频
π Molecular Orbitals of the Allyl Radical
Allyl radicals are three-carbon conjugated systems. They are readily formed as intermediates in halogenation reactions of alkenes involving the addition of halogen to the allylic carbon instead of the double bond. As seen in allyl cations and anions, each of the three sp2-hybridized carbon atoms in allyl radicals has an unhybridized p orbital. These orbitals combine to give three π molecular orbitals.
The allyl systems have identical molecular orbitals but differ in the number of π electrons.
The allyl systems have identical molecular orbitals but differ in the number of π electrons.
Radical Oxidation of Allylic and Benzylic Alcohols
Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are oxidized to aldehydes, while secondary allylic alcohols yield ketones. The redox reaction of potassium permanganate with an Mn(II) salt such as manganese sulfate (under either alkaline or acidic conditions), followed by thorough drying, yields the oxidizing agent: activated MnO2. While MnO2 is insoluble in the solvents used for the reaction, the...
Aldehydes and Ketones with Alcohols: Hemiacetal Formation
Similar to water, alcohols can add to the carbonyl carbon of the aldehydes and ketones. The addition of one molecule of alcohol to the carbonyl compound forms the hemiacetal or half acetal. As depicted below, in a hemiacetal, the carbon is directly linked to an OH and OR group.
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...
Radical Substitution: Allylic Chlorination
Typically, when alkenes react with halogens at low temperatures, an addition reaction occurs. However, upon increasing the temperature or under reaction conditions that form radicals, providing a low but steady concentration of halogen radicals, allylic substitution reaction is favored. This is because allylic hydrogens are very reactive as the formed intermediate is resonance stabilized. For example, when propene is treated with chlorine in the gas phase at 400 °C, it undergoes allylic...
Radical Reactivity: Electrophilic Radicals
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a low‐energy SOMO, which interacts...


