不被激活的烯酸与基胺的胺基化
Seth B Herzon1, John F Hartwig
1Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
Journal of the American Chemical Society
|October 22, 2008
概括
这项研究引入了一种新的催化反应,用于合未激活的氨基和烯酸. 该过程有效地在没有基质预激活的情况下形成分支产品,展示了罕见的分子间氨基-烯酸合.
科学领域:
- 有机金属化学 有机金属化学
- 催化剂是一种催化剂.
- 有机合成 有机合成
背景情况:
- 分子间氨基-烯酸合反应通常需要基质的预激活.
- 开发用于直接C-H功能化的催化系统是有机合成的一个关键挑战.
研究的目的:
- 描述一种新的催化方法,用于分子间添加未激活的dialkylamines到未激活的olefins.
- 为了研究这种新型氨基-烯联合反应的范围和机制.
主要方法:
- 使用一种胺复合物,[TaCl3(NEt2) 2 2 (2),作为催化剂.
- 采用1H NMR光谱和标记实验来阐明反应机制.
- 研究了一种相关的chloroanilido复合物的催化活性,[TaCl3(NMePh) ]2 (4).
主要成果:
- 实现了高收益率 (高达96%) 和分支插入产品的选择性.
- 证明了该反应能够合甲基胺的初级C-H键和较高基胺的二次C-H键.
- 通过90°C使用复合物4对烯酸添加N-烯酸胺的催化方法.
结论:
- 反应是通过一个eta2-imine复合物的循环限制生成进行的.
- 催化剂结构和基质分离影响反应性,混合化胺催化剂的活性较高.
- 这项工作提供了一种罕见的,有效的方法,用于在没有基质预激活的情况下进行分子间氨基-烯酸合.
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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...
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...
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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...
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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...
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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.
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