CuFe2O4纳米粒子催化芳香酮的不对称硅氢化反应  

Asymmetric Hydrosilation of Aromatic Ketones Catalyzed by CuFe_2O_4 Nanoparticles

作　　者：朱洁莲[1] 夏晓峰[1] 梁敏婷[1] 刘湘[1] 李和兴[2] 

机构地区：[1]江南大学化学与材料工程学院,食品胶体与生物技术教育部重点实验室,无锡214122 [2]上海师范大学资源化学教育部重点实验室,上海200234

出　　处：《高等学校化学学报》2016年第3期539-545,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:21402066)资助

摘　　要：分别采用共沉淀法、溶胶-凝胶法和溶剂热法制备得到CuFe_2O_4纳米粒子,以(R)-联萘二苯基膦[(R)-BINAP]为手性配体、聚甲基氢硅氧烷(PMHS)为硅氢化试剂,将制得的CuFe_2O_4纳米粒子用于催化芳香酮的不对称硅氢化反应.结果表明,溶剂热法能制得分散性好、粒径小且分布均匀的CuFe_2O_4纳米球,其催化活性明显优于其它2种方法.在添加剂t-Bu OK和t-BuOH的共同作用下,CuFe_2O_4纳米粒子的催化活性得以明显改善,最终得到一种高效的非均相催化体系CuFe_2O_4/t-Bu OK/t-BuOH.在室温和空气氛围下,用于催化芳香酮的不对称硅氢化反应,底物转化率和产物对映体过量值分别高达99%和92%.研究证实底物芳环上取代基的电子效应和空间位阻明显影响不对称硅氢化反应的结果.CuFe_2O_4纳米催化剂在外加磁场的作用下能较易从反应体系中分离回收,且催化剂经4次循环利用后仍具有较高的催化活性.CuFe2O4 nanoparticles were synthesized by coprecipitation,sol-gel and solvothermal methods,respectively. The asymmetric hydrosilation of aromatic ketones was catalyzed by CuFe2O4 nanoparticles,employing（ R）-BINAP[2,2＇-bis（ diphenylphosphino）-1,1＇-binaphthalene] as chiral ligand and polymethylhydrosiloxane as hydrosilating reagent. The results showed that compared to the others,the CuFe2O4 nanoparticles prepared by solvothermal method had spherical shape,small size,better dispersion,uniform distribution and excellent catalytic activities. Meanwhile,it was found that the catalytic activity of the CuFe2O4 nanoparticles was significantly improved with the addition of t-Bu OK and t-Bu OH. An efficient heterogeneous catalytic system CuFe2O4/ t-Bu OK / t-Bu OH was finally obtained. Under room temperature and air atmosphere,the conversion of the aromatic ketones and the enantiomeric excesses of the（ R）-1-arylethanols were up to 99% and92%,respectively,with the heterogeneous catalytic system. It was also confirmed that the electronic effect and steric hindrance of the groups on the aromatic ring distinctly affected the results of hydrosilation. And a possible mechanism was presented to explain the influence of some key factors on the reaction. Furthermore,it was demonstrated that the CuFe2O4 nanocatalyst could be easily separated from reaction system under an external magnetic field. And after recycling for four times,the catalyst could also have a high catalytic activity for the asymmetric hydrosilation.

关 键 词：不对称硅氢化反应 芳香酮 CuFe2O4纳米粒子 聚甲基氢硅氧烷 

分 类 号：O643.32[理学—物理化学] O621.34[理学—化学]