通过非酶性化催化剂对印多林的动态分辨率
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|November 2, 2006
概括
研究人员开发了一种新型的催化N-化方法,用于印度林的动力分辨率. 合成了新的性催化剂,增强了在没有酶的情况下对氨基分解的选择性.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 不对称的合成方法
背景情况:
- 动态分辨率对于获得质纯化合物至关重要.
- 酶催化分辨率是常见的,但对于氨基酸,非酶方法的探索较少.
- 印度林是药物化学中重要的异环基架.
研究的目的:
- 开发第一个催化N-化方法,用于印度林的动力分辨率.
- 设计和合成新的平面 - 脊髓催化剂以提高选择性.
- 探索非酶基催化剂的氨基溶解.
主要方法:
- 合成新的平面 - 合性PPY衍生的催化剂,系统修改合性环境.
- 这些催化剂的应用在通过N-化对印度林的动力分辨率.
- 基于选择性因素和效率的催化剂性能评估.
主要成果:
- 成功开发了第一个催化N-化方法,用于印度的动力分辨率.
- 证明PPY衍生催化剂中系统修改的性环境可以提高选择性.
- 鉴定了一种罕见的非酶基化催化剂的例子,用于氨基动态分辨率.
结论:
- 描述的方法为有价值的印度衍生物的选合成提供了一条新的途径.
- 开发的平面 - 性催化剂代表了对氨酸分辨率的不对称催化剂的重大进步.
- 这项工作扩大了有机合成中非酶动力学分辨率策略的工具包.
相关概念视频
01:19Amines 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...
01:19α-Hydroxy Ketones via Reductive Coupling of Esters: Acyloin Condensation Overview
The pinacol and McMurry reactions involve the reductive coupling of ketones or aldehydes. Similarly, the bimolecular reductive coupling of two ester molecules in the presence of sodium metal in an aprotic solvent yields an α-hydroxy ketone product. The α-hydroxy ketone is also called acyloin, so the reaction is referred to as ‘acyloin condensation.’
02:24Reduction 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.
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.
01:10α-Alkylation of Ketones via Enolate Ions
Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the strong interaction...
02:27Preparation of Alkynes: Alkylation Reaction
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...