离子启动了中型环形形成:阿斯特里斯库诺利德D的总合成
Barry M Trost1, Aaron C Burns, Mark J Bartlett
1Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA. bmtrost@stanford.edu
Journal of the American Chemical Society
|January 13, 2012
概括
研究人员首次合成了天然产品asteriscunolide D. 这九步过程有效地创造了紧张的宏循环,产生了最生物活跃的形式.
科学领域:
- 有机化学 有机化学
- 自然产品的合成自然产品的合成
- 药用化学 医学化学
背景情况:
- 胡穆伦天然产品具有显著的生物活性.
- 阿斯特里斯库诺利德D是一种复杂的分子,具有具有挑战性的11个成员的环状结构.
- 之前的合成途径无法获得最生物活跃的阿斯特里斯库诺利德D的形式.
研究的目的:
- 为了实现第一个全合成的asteriscunolide D.
- 制定一个无保护组的合成策略.
- 为了获得asteriscunolide D.的最生物活性异构体.
主要方法:
- 灾难选择性离子启动了循环,形成了11个成员的环.
- 立体特异型乙烯激活-消除用于选择性E-olefin形成.
- 用Zn-ProPhenol催化对抗选择性添加和Ru-催化基-基合,用于立体化学控制和布特化物形成.
主要成果:
- 在没有保护组的情况下,成功合成了星素化物D的九步合成.
- 通过一种新的循环化策略形成紧张的11个成员的宏循环.
- 立体选择性合成提供了对生物活性最强的asteriscunolide D同位素的获取.
结论:
- 开发的合成路线是高效的,避免保护群体.
- 合成提供了一种可靠的方法来获取具有生物活性的asteriscunolide D.
- 这项工作促进了复杂的自然产品的合成,并促进了进一步的生物研究.
相关概念视频
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
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...
Electrophilic Addition to Alkynes: Halogenation
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.

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