外消旋硝基烯丙醇經Rauhut-Currier反應之動力學光學分割
No Thumbnail Available
Date
2015
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
動力學光學分割為簡單有效分離外消旋混合物的方法，而Rauhut-Currier 反應是生成碳-碳鍵的重要方式。本實驗嘗試以丙烯醛與外消旋硝基烯丙醇進行Rauhut-Currier反應，結合動力學光學分割，以去甲氧基奎寧為對掌三級胺催化劑，乙腈為溶劑，於室溫下反應，得到非鏡像異構比為1:1的產物，兩非鏡像異構物之鏡像超越值分別為24%和31%，但回收起始物仍為外消旋混合物；另亦以1,4-二氮雜二環[2.2.2]辛烷與對掌二級胺共催化的方式，使用苯甲酸為添加劑，於-20 oC的溫度下反應，非鏡像異構比最高為4.4:1，但產物與起始物之鏡像選擇性皆不理想。
Kinetic resolution is a conventional and effective way to separate recemates. Rauhut-Currier reaction is an important method to form new carbon-carbon bond. In this study we combine Rauhut-Currier reaction and kinetic resolution. Racemic nitroallylic alcohol and acrolein are catalysted by cupreine in the presence of acetonitrile at ambient temperature. Two diastereomers were obtained and the enantiomeric excess are 24% and 31%, respectively. Recovered starting material is still racemic mixture. On the other way, we use 1,4-diazabicyclo[2.2.2]octane and chiral secondary amine as co-catalyst to optimize the reaction conditions. Thereaction use benzoic acid as additive under -20 oC. The diastereomer ratio can be obtained in 4:1, but enantioseletivity of product and recovered starting material are not good.
Kinetic resolution is a conventional and effective way to separate recemates. Rauhut-Currier reaction is an important method to form new carbon-carbon bond. In this study we combine Rauhut-Currier reaction and kinetic resolution. Racemic nitroallylic alcohol and acrolein are catalysted by cupreine in the presence of acetonitrile at ambient temperature. Two diastereomers were obtained and the enantiomeric excess are 24% and 31%, respectively. Recovered starting material is still racemic mixture. On the other way, we use 1,4-diazabicyclo[2.2.2]octane and chiral secondary amine as co-catalyst to optimize the reaction conditions. Thereaction use benzoic acid as additive under -20 oC. The diastereomer ratio can be obtained in 4:1, but enantioseletivity of product and recovered starting material are not good.
Description
Keywords
動力學光學分割, Rauhut-Currier 反應, Kinetic Resolution, Rauhut-Currier Reaction