Large-pore mesoporous ethane-silicas as efficient heterogeneous asymmetric catalysts
Large-pore mesoporous ethane-silicas with trans-(1R,2R)-diaminocyclohexane protruding in the channel were synthesized by one-step condensation of 1,2-bis(trimethoxysilyl)ethane and N-(triethoxysilyl)propyl-( )-(1R,2R)-diaminocyclohexane in acidic medium using P123 as template. Mesoporous materials are used as catalysts for the asymmetric transfer hydrogenation (ATH) of acetophenone after complexing Rh(cod)Cl2. The catalyst with SBA-15 type mesostructure exhibits higher activity, compared to the catalyst with MCM-41 type mesostructure. The post-decoration of trans-(1R,2R)-diaminocyclohexane in the pore of SBA-15 type mesoporous material was further demonstrated by reacting with ptoluenesulfonyl chloride. The modified material (complexed with RuCl2(p-cymene)2) gives an enhanced 66％ ee (R) for the ATH of acetophenone under air atmosphere in HCOONa- H2O, while only 2％ ee (S) is observed on the original material under identical reaction conditions.
D. M. Jiang J. S. Gao Q. H. Yang C. Li
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023
国际会议
北京
英文
2007-08-12（万方平台首次上网日期，不代表论文的发表时间）