一个快速的阿萨-自行车合成从Dendralenes和Imines
Yi-Min Fan1, Josemon George1, Jiao Yu J Wang2
1Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
Organic letters
|October 6, 2023
概括
这项研究引入了imines作为aza-Diels-Alder反应与树枝蛋白的有效参与者,使复杂的异类结构的合成成为可能. 该反应具有很高的选择性,并通过一个阶段性的离子机制进行.
科学领域:
- 有机化学 有机化学
- 合成化学 合成化学
- 催化剂是一种催化剂.
背景情况:
- 迪尔斯-阿尔德反应是聚碳化合物合成的基石.
- 登德拉林是复杂分子架构的多功能构建块.
- 已建立的方法主要利用基于碳的二氧化物.
研究的目的:
- 为了探索与树突烯的正式 [4 + 2] 循环添加中的 imines 的反应性.
- 开发一种新型的合成路径,以获得六和八异可因衍生物.
- 调查这种新变化的机制和选择性.
主要方法:
- 在与 [3]dendralenes 的分子间循环添加中使用 imines 作为二烯基.
- 采用易斯酸催化,促进正式的阿扎-迪尔斯-阿尔德反应.
- 执行DFT计算 (ωB97XD/Def2-TZVP//M06-2X/6-31+G(d,p)) 以阐明反应机制.
主要成果:
- 证明了 imines 在正式 [4 + 2] 循环添加与树枝烯的能力.
- 在形成异二醇结构中实现了高的区域和立体选择性.
- 确定了一个阶段性离子机制,并解释了一个意想不到的Z → E烯酸异构化.
结论:
- 胺是基于树枝烯的循环添加物的有效合作伙伴,扩大了聚碳化合物合成的范围.
- 开发的正式的aza-Diels-Alder反应为有价值的异诺林支架提供了一条选择性的途径.
- 计算研究为反应的机械复杂性提供了关键的见解.
相关概念视频
Preparation of 1° Amines: Azide Synthesis
4.0K
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...
4.0K
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
3.0K
The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the...
3.0K
Preparation of 1° Amines: Gabriel Synthesis
3.6K
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...
3.6K
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
2.9K
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.
2.9K
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
1.9K
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...
1.9K
Preparation of Amides
3.0K
Amides are synthesized by treating carboxylic acids with amines in the presence of dehydrating agents like dicyclohexylcarbodiimide (DCC).
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
3.0K


