使用 redox-relay 策略的非循环基醇的 Enantioselective Heck 合物
Erik W Werner1, Tian-Sheng Mei, Alexander J Burckle
1Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA.
Science (New York, N.Y.)
|December 15, 2012
概括
这项研究引入了一种对抗选择性的Heck合反应,用于制造烯碳化合物. 新型催化剂系统实现了高的区域选择性和反选择性,为复杂分子提供了一条新的合成路线.
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:
- 不对称的赫克合对合成复杂的有机分子至关重要.
- 对迁徙插入和β-化物消除的选择性的有限理解阻碍了进展.
研究的目的:
- 开发一种对基碳酸产品合成的酶选择性Heck合变体.
- 阐明反应中调节区域选择性和酶选择性的因素.
主要方法:
- 使用了一种新型的催化剂系统进行不对称的Heck合.
- 使用阿里尔迪亚佐尼盐作为源.
- 研究了与非循环醇基质的反应.
主要成果:
- 实现了β,gamma或delta-aryl碳酸产品的酶选择合成.
- 在迁移的插入和基不和迁移中表现出高的区域选择性.
- 从相反的基构成中观察到的反体产物,独立于基质性.
结论:
- 开发的催化剂系统使得烯碳烯化合物的高效酶选择性合成成为可能.
- 获得了对区域选择性和enantioselectivity的机制性见解.
- 提供了一种使用易于获取的配体和阿里尔迪亚佐尼盐的多功能方法.
相关概念视频
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.
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
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.
01:11Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.