协同进行的催化氨化和[2,3]-斯蒂文斯对三级氨基的重新排列
Arash Soheili1, Uttam K Tambar
1Department of Biochemistry, Division of Chemistry, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, USA
Journal of the American Chemical Society
|July 29, 2011
概括
这项研究引入了使用三级氨基的催化氨化,从而实现了新的催化史蒂文斯重组. 该方法在温和条件下实现了高产量和选择性,具有广泛的基质范围.
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:
- 三级胺在金属催化基替代中通常是较差的核友.
- 在有机合成中,开发新的C-N键形成方法至关重要.
研究的目的:
- 开发一种使用三级胺作为核的新型催化合氨基氨基化反应.
- 建立一个双重反应,涉及化生成和[2,3]重排,模仿催化史蒂文斯重排.
主要方法:
- 使用三级氨基和基碳酸盐作为基质.
- 采用催化剂用于基替代和重新排列.
- 研究的反应条件,催化剂负载和基质范围.
- 进行了机理学研究以阐明反应途径.
主要成果:
- 在金属催化基替代中实现了第三级氨基的分子间核友性攻击的第一个例子.
- 开发了一种双重氨基化生成/[2,3]重排,一种催化史蒂文斯重排.
- 在温和条件下与广泛的基板具有证明的兼容性.
- 获得的产品具有高产量和出色的 diastereoselectivities.
- 机理学研究表明可逆的中间体形成.
结论:
- 开发的催化系统为合成复杂分子提供了一条有效的途径.
- 这项工作扩大了三级胺在催化C-N键形成反应中的实用性.
- 双重反应提供了一个强大的策略,用于访问有价值的有机结构.
相关概念视频
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview
In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...
Preparation of Amines: Alkylation of Ammonia and Amines
Alkylation is one of the methods used to prepare amines. Direct alkylation of ammonia or a primary amine with an alkyl halide gives polyalkylated amines along with a quaternary ammonium salt through successive SN2 reactions. This process of making the quaternary salt through the direct alkylation method is called exhaustive alkylation.
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Amines to Amides: Acylation of Amines
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...


