• 文献标题:   Primary amine-thiourea grafted graphene-based heterogeneous chiral catalysts for highly enantioselective Michael additions
  • 文献类型:   Article
  • 作  者:   BADR SM, AZLOUK M, ZOR E, BINGOL H, DURMAZ M
  • 作者关键词:   metalfree asymmetric catalysi, heterogeneous catalyst, bifunctional carbocatalyst, graphene oxide, asymmetric michael addition
  • 出版物名称:   MOLECULAR CATALYSIS
  • ISSN:   2468-8231
  • 通讯作者地址:  
  • 被引频次:   3
  • DOI:   10.1016/j.mcat.2022.112383 EA MAY 2022
  • 出版年:   2022

▎ 摘  要

Heterogeneous asymmetric catalysis based on earth-abundant carbon materials put together the advantages for the ease of separation, simple regeneration, and high stability of solid catalysts as well as acts as low-cost, environmentally friendly metal-free alternative to the metal-based catalysts. Two new bifunctional carbocatalysts [(S,S) and (R,R) GO-PATU] were prepared by anchoring enantiomerically pure organosilanes bearing primary amine and thiourea groups to the graphene oxide (GO) skeleton covalently via silane coupling reaction. The surface modification of GO was analyzed by a combination of Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM) techniques. The catalytic performances of graphene-based materials were investigated in the asymmetric Michael addition reactions of alpha,alpha-disubstituted-aldehydes to nitrostyrenes and N-substituted-maleimides. The effects of solvents and Bronsted basic or acidic additives were evaluated using both catalysts and good yields (up to 85%) and stereoselectivities (up to 95% ee) were obtained in dichloromethane at room temperature in the presence of L- and D-camphorsulfonic acid. Besides, recycling and reusing studies of the catalysts were successfully performed.