基因的选择性α-化-化:简要的获取配置定义的四替代基因
Prachi Shah1, Maciej Dajek1, Urszula Klimczak1
1Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
这项研究引入了一种新的一催化方法,用于基的直接alpha-borylation-arylation. 这种方法有效地合成了多功能乙烯基酸构建块,用于复杂的分子构建.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 合成方法论 合成方法论
背景情况:
- 传统的化和异质化化产生β替代产物.
- 开发区域选择性方法来实现基的α功能化仍然是一个挑战.
- 乙烯基酸盐是有机合成中的关键中间体.
研究的目的:
- 开发一种新的方法,用于直接的alpha-borylation-arylation的alkynes.
- 在基因的功能化中实现高的区域和立体选择性.
- 为了证明合成的乙烯基酸盐作为构建块的实用性.
主要方法:
- 一个的催化碳磁化.
- 随后使用 bis ((pinacolato) diboron (B2pin2) 或 pinacolborane (HBpin) 的化.
- 为区域选择性和立体选择性优化反应条件.
主要成果:
- 实现了基因的同选择性α-玻里化-化.
- 在三替代乙烯基酸盐的形成中表现出高效率和选择性.
- 利用乙烯基酸盐合成配置定义的四位置换烯酸.
- 介绍了Tamoxifen的两步合成方法.
结论:
- 开发的方法提供了一条强大的新途径,可以获得alpha-borylated alkynes.
- 合成的乙烯基酸盐是构建复杂有机分子的宝贵前体.
- 这种方法为合成立体定义的烯酸和制药提供了一条有效的途径.
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相关概念视频
Preparation of Alkynes: Alkylation Reaction
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.
Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
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.
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
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.
Electrophilic Addition to Alkynes: Halogenation
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 of Alkynes: Dehydrohalogenation
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.
Electrophilic Addition to Alkynes: Hydrohalogenation
