颠覆印烯区域选择性和印拉克坦V的合成
Sarah M Bronner1, Adam E Goetz, Neil K Garg
1Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.
Journal of the American Chemical Society
|March 1, 2011
概括
研究人员设计了一种新型的indolyne,与典型的4,5-indolynes相比,在反应中逆转区域选择性. 这种方法使得替代性醇和醇类化合物的受控合成成为可能.
科学领域:
- 有机化学 有机化学
- 合成化学 合成化学
- 药用化学 医学化学
背景情况:
- 4,5-英多林通常在化学反应中表现出可预测的区域选择性.
- 控制区域选择性对于合成复杂的醇衍生物至关重要.
研究的目的:
- 设计和合成一种具有逆转区域选择性的新型的indolyne.
- 开发一种计算方法来预测一个区域的选择性.
- 为了证明C4替代的醇类化合物的新合成途径.
主要方法:
- 设计和合成一种新型的indolyne前体.
- 应用简单的计算模型来预测区域选择性.
- 核友添加和循环添加反应,使用新型的Indolyne.
- 作为概念验证的印洛V的合成.
主要成果:
- 合成的英多林在核友添加和循环添加反应中表现出逆转的区域选择性.
- 计算预测准确地指导了区域选择性结果.
- 成功合成了具有高区域控制的新型化物替代性醇.
- 证明了一种非传统的途径到C4替代的醇化物,包括氨酸V.
结论:
- 新型的Indolyne提供了一个强大的工具,用于控制醇合成中的区域选择性.
- 计算预测提供了一个可靠的策略,用于设计与不对称的arynes反应.
- 这种方法扩大了合成获取有价值的醇类化合物的途径.
相关概念视频
02:36Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
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.
01:33Regioselective Formation of Enolates
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.
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
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...
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.