Rh2 (((II) 催化的基迁移反应:从β-基 styryl 化物中选择性合成3-nitroindoles
Benjamin J Stokes1, Sheng Liu, Tom G Driver
1Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
Journal of the American Chemical Society
|March 16, 2011
概括
催化剂有助于在化中提取电子的组迁移,产生3替代的. 这种反应为有价值的醇衍生物提供了一条选择性途径.
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:
- 印衍生物在制药和材料科学中普遍存在.
- 有效的合成路径到替代的内是非常受欢迎的.
- 迁移反应为分子构造提供了独特的途径.
研究的目的:
- 开发一种新型的催化方法来合成3替代的.
- 在这种转换中研究各种电子吸收群体的迁移能力.
- 用碳酸盐复合物作为高效的催化剂.
主要方法:
- 使用碳酸盐复合物 (1 mol %) 作为催化剂.
- 反应β-置换的乙化酸乙烯与各种电子吸收组.
- 分析电子提取组迁移的区域选择性.
主要成果:
- 从β替代的乙酸乙烯中选择性形成3替代的醇.
- 确定了迁移能力的相对顺序: ≪ 胺基 < H < 硫 < ≪ .
- 证明了碳酸盐复合物的催化效率.
结论:
- 催化迁移提供了一种选择性和高效的方法,用于醇合成.
- 迁移适应性顺序为基板设计提供了宝贵的见解.
- 这种方法扩展了构建复杂的内部结构架构的工具包.
相关概念视频
Preparation of 1° Amines: Azide Synthesis
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Preparation of Nitriles
One of the common methods to prepare nitriles is the dehydration of amides. This method requires strong dehydrating agents like phosphorous pentoxide or boiling acetic anhydride for converting amides to nitriles. Another reagent namely, thionyl chloride also accomplishes the dehydration of amides, where amide acts as a nucleophile. The first step of the mechanism involves the nucleophilic attack by the amide on the thionyl chloride to form an intermediate. In the next step, the electron pairs...
Electrophilic Aromatic Substitution: Nitration of Benzene
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Oximes can be reduced to primary amines using catalytic hydrogenation, hydride reduction, or sodium metal reduction. The reduction of aliphatic and aromatic nitro compounds to primary amines takes place by either catalytic hydrogenation or by using active metals like Fe, Zn, and Sn in the presence of an acid.
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
SN2 Reaction: Stereochemistry
In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.


