合成和反应的素稳定单体类比的alkyneses
Juliette Berthe1, Juan Manuel Garcia, Edgar Ocando
1Université de Toulouse, UPS and CNRS, LHFA UMR 5069, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France.
Journal of the American Chemical Society
|September 15, 2011
概括
研究人员合成了一种新的C-phosphino-Ge-aminogermyne,一种具有独特结合力的化合物. 这种生殖基因异构,形成稳定的N-异环生殖基因,展示了连接体迁移化学.
科学领域:
- 有机金属化学 有机金属化学
- 主群 化学 化学
背景情况:
- 细菌体是高度反应的低协调的细菌体物种.
- 稳定细菌对于研究它们独特的电子性质至关重要.
研究的目的:
- 为了合成和描述第一个可分离的C-phosphino-Ge-aminogermyne.
- 为了研究这种新型细菌衍生物的反应性和结构性质.
主要方法:
- 合成C-phosphino-Ge-aminogermyne使用氨酸连接物稳定.
- 进行X射线衍射分析,以确定分子结构和键长度.
- 异构反应形成N-异环基米烯.
主要成果:
- 成功分离和表征一个C-phosphino-Ge-aminogermyne.
- X射线衍射揭示了一种显著长的Ge-C键,介于单键和双键之间.
- 异构化导致通过氨酸连接体迁移形成稳定的N-异环细菌烯.
结论:
- 这项研究报告了第一个可分离的C-phosphino-Ge-aminogermyne,由素连接体稳定.
- 观察到的Ge-C键长度支持对具有π-捐赠替代体的生殖基的理论预测.
- 异构化途径显示出一种新的途径,可以达到稳定的N-异环基米烯.
相关概念视频
02:34Preparation of Alkynes: Dehydrohalogenation
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.
02:38Electrophilic 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.
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.
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
01:19Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
The Wittig reaction is the conversion of carbonyl compounds-aldehydes and ketones-to alkenes using phosphorus ylides, or the Wittig reagent. The reaction was pioneered by Prof. Georg Wittig, for which he was awarded the Nobel Prize in Chemistry.
02:35Electrophilic 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.