/单酸胺催化非对称化N-胺的N-胺
Natasa Mrsić1, Adriaan J Minnaard, Ben L Feringa
1University of Groningen, Stratingh Institute for Chemistry, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Journal of the American Chemical Society
|June 18, 2009
概括
/PipPhos催化 N-烯酸乙 imines 的不对称化产生高度反选择性的二次胺. 随后的降解保护提供了具有完全enantioselectivity的初级氨基.
科学领域:
- 有机化学 有机化学
- 不对称的催化剂.
- 绿色化学 绿色化学
背景情况:
- 胺胺是制药和精细化学品中至关重要的构建模块.
- 有效的非对称合成方法对于生产纯化合物至关重要.
- N-烯酸乙胺胺是氨基合成的多功能前体.
研究的目的:
- 开发一种高度选择性的方法,用于合成合性N-烯酸乙氨基胺衍生物.
- 为了研究替代剂对抗选择性的影响.
- 建立一个简单的去保护策略,以获取初级氨基.
主要方法:
- 使用/PipPhos催化剂系统不对称化N-乙胺胺.
- 反应条件的优化以最大限度地提高酶选择性.
- 使用三化酸对二次氨基的氧化降解保护.
主要成果:
- 在不对称化过程中获得非常高的反选择性 (高达>99%).
- 证明了在环中的电子捐赠替代物增强了酶选择性.
- 成功地将二次氨基酸转化为初级氨基酸,具有良好的产量,完全保留了酶选择性,特别是在2-甲基基替代基质中.
结论:
- /PipPhos 系统对于 N-烯酸乙 imines 的不对称化非常有效.
- 开发的方法提供了一条可靠的途径,以获得基丰富的初级氨基.
- 这种方法为合成含有奇拉胺的分子提供了有价值的工具.
相关概念视频
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The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
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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...
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Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
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If the pH is low or the solution is too acidic, the reaction slows down in the...
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...
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