Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with...Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with an ionic liquid(IL)linkage via the one‐pot reaction of imidazole‐TsDPEN‐N‐Boc with 3‐(trimethoxysilyl)propyl bromide in the SBA‐15 mesopores.After coordination to Rh,the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation,achieving 97%conversion with 93%ee,which was comparable to their homogeneous counterparts.The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage(93 h^(–1)vs.33 h^(–1)),attributed to the phase transfer and formate‐enriching ability of the IL linkage.Furthermore,the effect of the pH on the reaction rate of the solid catalyst was investigated,preventing reaction rate retardation during the catalytic process.The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.展开更多
A novel route for dinitrification of N-phenylbenzenesulfonamide to synthesize N-(2,4-dinitrophenyl)benzenesulfonamide has been developed.The method features convenient operation and good functional group tolerance.Thi...A novel route for dinitrification of N-phenylbenzenesulfonamide to synthesize N-(2,4-dinitrophenyl)benzenesulfonamide has been developed.The method features convenient operation and good functional group tolerance.This reaction may go through a nitrogen dioxide radical(NO_(2)·)intermediate,which is generated by the thermal reaction process of sodium nitrate and ammonium persulfate.In addition,it provides direct approach for the preparation of 2,4-dinitroaniline derivatives which are crucial intermediate for the synthesis of benzimidazoles and quinoxaline derivatives.展开更多
文摘Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge.Herein,we report the immobilization of TsDPEN on SBA‐15 with an ionic liquid(IL)linkage via the one‐pot reaction of imidazole‐TsDPEN‐N‐Boc with 3‐(trimethoxysilyl)propyl bromide in the SBA‐15 mesopores.After coordination to Rh,the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation,achieving 97%conversion with 93%ee,which was comparable to their homogeneous counterparts.The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage(93 h^(–1)vs.33 h^(–1)),attributed to the phase transfer and formate‐enriching ability of the IL linkage.Furthermore,the effect of the pH on the reaction rate of the solid catalyst was investigated,preventing reaction rate retardation during the catalytic process.The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.
文摘A novel route for dinitrification of N-phenylbenzenesulfonamide to synthesize N-(2,4-dinitrophenyl)benzenesulfonamide has been developed.The method features convenient operation and good functional group tolerance.This reaction may go through a nitrogen dioxide radical(NO_(2)·)intermediate,which is generated by the thermal reaction process of sodium nitrate and ammonium persulfate.In addition,it provides direct approach for the preparation of 2,4-dinitroaniline derivatives which are crucial intermediate for the synthesis of benzimidazoles and quinoxaline derivatives.
