最近在过渡金属催化基因的Büchner反应方面取得的进展
Guang Ma1, Kua-Fei Wei1, Man Song1
1College of Sciences and College of Forestry, Henan Agricultural University, Zhengzhou, Henan 450002, China. wenboshen@henau.edu.cn.
Organic & biomolecular chemistry
|June 16, 2023
概括
合成七个环,往往具有挑战性,现在更容易获得. 过渡金属催化布赫纳反应为制造这些有价值的有机分子提供了高效的途径.
科学领域:
- 有机化学 有机化学
- 合成化学 合成化学
背景情况:
- 中等大小的环,特别是七环环,是有机分子中重要的结构图案.
- 由于热效应和跨环相互作用,它们的合成具有挑战性,使传统的循环化途径的效率低于较小的环.
研究的目的:
- 审查过渡金属催化Büchner反应的最新进展,以合成七个成员的环.
- 突出这些反应的高效合成程序和机械洞察力.
主要方法:
- 专注于过渡金属催化Büchner环扩张反应,涉及基.
- 根据使用的催化剂类型对反应进行分类.
- 在适用时讨论机械论的理由.
主要成果:
- 开发多样化和高效的合成工艺,用于七段环结构.
- 在温和的实验条件下成功地应用了Büchner反应.
- 促进先前具有挑战性的七个成员环框架的合成.
结论:
- 过渡金属催化Büchner反应代表了获得七个环的重大突破.
- 这些方法提供了高效和温和的途径,以合成有价值的,功能化的七肢环产品.
- 这一领域的持续研究有望进一步开发复杂有机支架的合成策略.
相关概念视频
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
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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.
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02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
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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.
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02:27Preparation of Alkynes: Alkylation Reaction
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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.
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02:38Electrophilic Addition to Alkynes: Halogenation
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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.
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02:34Preparation of Alkynes: Dehydrohalogenation
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Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
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02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
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Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
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...
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