直接用硫酸盐直接替代一次性氨基胺
Xue-Song Wu1, Yan Chen, Man-Bo Li
1Joint Laboratory of Green Synthetic Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
Journal of the American Chemical Society
|August 30, 2012
概括
这项研究引入了一种新的催化反应,从初级胺和硫酸盐盐中产生酸硫. 该方法对区域和立体选择性提供了出色的控制,产生了多样化和光学纯净的产品.
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:
- 基硫是有价值的合成中间体.
- 氨酸胺的直接功能化仍然是一个挑战.
- 目前用于不对称的基硫合成的方法在基质范围上有局限性.
研究的目的:
- 开发一种新的催化方法,用于直接合成酸硫.
- 为了实现高的区域和立体选择性,在主要氨基胺的替代.
- 为了扩大基质范围,以不对称地合成合性合硫.
主要方法:
- 在初级氨酸胺中,用硫酸盐直接替代NH(2) 组,用催化.
- 使用[Pd(基) Cl](2) 催化剂与1,4-bis(diphenylphosphino) butan (dppb) 连接体进行α选择性替代.
- 采用 1,1'-bi-2-naphthol (BINOL) 连接体,用于与奇拉胺的不对称合成.
主要成果:
- 在形成酸硫中获得了优异的区域和立体选择性.
- 合成结构多样化的酸硫,具有良好的至优良的产量,具有独特的E选择性.
- 从不对称的氨基胺中获得具有高光学纯度和优异的反体过量 (ee) 保留的合性氨基硫.
结论:
- 开发的催化系统提供了一条有效的途径,以α-分支和α-合合硫.
- 这种方法补充了现有的不对称策略,允许使用不对称的基电友.
- 反应为构建具有高立体化学控制的复杂分子提供了有价值的工具.
相关概念视频
Amines to Sulfonamides: The Hinsberg Test
The Hinsberg test is a method to identify primary, secondary and tertiary amines, named after its pioneer, Oscar Hinsberg. Here, amines are treated with benzenesulfonyl chloride, also known as the Hinsberg reagent, in the presence of an excess of aqueous base, followed by acidification. Based on the nature of the amines, different changes are observed.
Generally, a primary amine reacts with the Hinsberg reagent to produce an N-substituted benzenesulfonamide. The electron-withdrawing sulfonyl...
Generally, a primary amine reacts with the Hinsberg reagent to produce an N-substituted benzenesulfonamide. The electron-withdrawing sulfonyl...
Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
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 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...

