摘要
以L-缬氨酸、L-亮氨酸和L-苯丙氨酸为原料合成了未见报道的4种咪唑基手性硫醚化合物,并将咪唑基硫醚固载到SiO2上制备了二氧化硅固载咪唑基手性硫醚配体,用元素分析、热重等手段进行了表征;进而与PdCl2反应得到二氧化硅固载咪唑基手性硫醚-钯(II)催化剂,用XPS等方法对其进行了表征.考察了该催化剂在Suzuki反应中的催化性能.结果表明,在以溴苯与苯硼酸为底物的Suzuki反应中,该催化剂用量为底物的0.75%、反应时间为5 h、温度为80℃时,溴苯的转化率可达95%.
Using L-valine,L-leucine,L-phenylalanine as starting materials,the imidazole ring was con-densed by ring fragments and hydroxyl group was induced by the reduction of carboxyl of the amino acids.And then through chlorination and subsequent substitution by thiols,chiral imidazole thioethers were syn-thesized and their structures were characterized by 1H NMR,13C NMR,IR and HRMS.Using SiO2 as a car-rier,chiral imidazole thioethers were loaded and they were characterized by the DTA and elemental analysis.The results showed that the covalent bond was formed between thioether and silica.SiO2-supported chiral imidazole thioether ligands were separately coordinated to PdCl2 and the catalysts were characterized by XPS.The results showed that the palladium was coordinated with SiO2-supported chiral imidazole thiother ligand which can stabilize the catalyst,and the carbene might participate in the coordination with Pd.The activity of the catalysts was studied in the Suzuki coupling reaction.Under the optimum reaction conditions,which the reaction temperature was 80 ℃ and the amount of the catalyst was 0.75% of the substrate,the conversion of brombenzene was 95% for 5 h.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2011年第11期1828-1834,共7页
Chinese Journal of Organic Chemistry
基金
国家自然科学基金(No.20902017)资助项目
