在催化作用下添加酸化物到终端基中
Tomohiro Iwai1, Tetsuaki Fujihara, Jun Terao
1Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.
Journal of the American Chemical Society
|April 24, 2009
概括
一个具有N-异环碳联体的复合物有效地从酸和基因中合成不和和乙烯化物. 这种方法还可以通过催化方式生产替代的 furan.
科学领域:
- 有机金属化学 有机金属化学
- 催化剂是一种催化剂.
- 有机合成 有机合成
背景情况:
- 在现代化学中,开发高效的催化方法来合成复杂的有机分子至关重要.
- 复合物,特别是那些含有N-异环碳素 (NHC) 连接体的复合物,在各种催化转化中表现有前途.
- 在添加反应中控制区域和立体选择性仍然是有机合成的一个关键挑战.
研究的目的:
- 为了研究的N-异环碳 (NHC) 复合物的催化活性,特别是IrCl,在添加芳香酸化物到终端基中.
- 探索连接体变异 (NHC与氨酸) 对反应结果的影响,包括脱碳化途径.
- 证明开发的催化系统对于合成有价值的有机化合物,如替代的有用性.
主要方法:
- 用一种复合物,IrCl () () (IPr),与各种芳香酸化物和终端基进行了催化加法反应.
- 进行了连接体查,比较了NHC连接体 (IPr) 与素连接体 (RuPhos) 的性能.
- 对反应条件进行了优化,以实现高区域和立体选择性.
- 合成的产品使用标准光谱技术进行了表征.
主要成果:
- NHC复合物,IrCl(cod) ((IPr),成功催化了芳香酸化物添加到终端基,产生具有高区域性和立体选择性的 (Z) -β-chloro-α,β-不和子.
- 将NHC连接体替换为素连接体 (RuPhos) 导致脱碳化并形成 (Z) - 乙烯化物.
- 由IrCl ((cod) ((IPr) 催化反应成功地应用于合成2,5-非替代的 furan.
结论:
- 这项研究强调了IrCl ((cod) ((IPr) 综合体作为 (Z) -β-chloro-alpha,β-不和子选择性合成的催化剂的有效性.
- 连接物选择对反应途径产生重大影响,使得可以进入不同的产品类 (基与乙烯化物).
- 开发的方法为功能化 furan 的催化合成提供了一个有价值的途径.
相关概念视频
Electrophilic Addition to Alkynes: Hydrohalogenation
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.
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 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.
Alkynes 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.
Reduction 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.
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.


