Homogeneous Chiral Catalysis in Heterogeneous Nanoreactors

The heterogeneous asymmetric catalysis is becoming a fascinating area for both the academic research and the commercial applications. However, the low activity and enantioselectivity of most chiral solids impedes the practical applications of heterogeneous asymmetric catalysis. The transformation of homogeneous asymmetric catalysts into heterogeneous ones would benefit the economic and green process for the production of chiral chemicals. The chiral solid catalysts prepared by immobilization method usually exhibits low efficiency due to the inhomogeneous distribution of the active species and altered microenvironment of the homogeneous asymmetric catalysts. Therefore, new strategies are desired to be developed for the preparation of high‐\performance chiral solids for heterogeneous asymmetric catalysis. In recent years, we investigated the asymmetric catalysis in the nanopore of mesoporous materials and observed the pore confinement effect which could be used to increase the enantioselectivity (ee%) of the solid chiral catalysts [1]. The novel chiral porous materials, the chiral periodic mesoporous organosilicas (chiral PMOs), were synthesized and the relation between the porous structure and the catalytic performance of the chiral PMOs was elucidated [2]. Moreover, we developed an efficient strategy for encapsulation of transition metal complexes in the nanocage of mesoporous silicas [3]. The transition metal complexes encapsulated in the nanocages can move freely during the catalytic process because of no strong interactions between the catalysts and the solid supports. This strategy could be employed for the preparation of chiral solid catalysts with high activity and enantioselectivity owing to the cooperative activation effect. More recently, we extended the asymmetric catalysis to the nanochannels of CNT [4]. Pt nanocatalyst encapsulated inside CNTs modified by CD was found to be more active and enantioselective than Pt nanocatalyst on the outer surface of CNTs for the asymmetric hydrogenation of α‐\ketoesters, which shows the unique effect of nano‐\channels of CNTs as nanoreactors for asymmetric catalysis. The asymmetric catalysis in the nanoreactor opens an opportunity for developing novel, highly active and enantioselective heterogeneous chiral catalysts.The heterogeneous asymmetric catalysis is becoming a fascinating area for both the academic research and the commercial applications. However, the low activity and enantioselectivity of most chiral solids impedes the practical applications of heterogeneous asymmetric catalysis. The transformation of homogeneous asymmetric catalysts into heterogeneous ones would benefit the economic and green process for the production of chiral chemicals. The chiral solid catalysts prepared by immobilization method usually exhibits low efficiency due to the inhomogeneous distribution of the active species and altered microenvironment of the homogeneous asymmetric catalysts. Therefore, new strategies are desired to be developed for the preparation of high‐\performance chiral solids for heterogeneous asymmetric catalysis. In recent years, we investigated the asymmetric catalysis in the nanopore of mesoporous materials and observed the pore confinement effect which could be used to increase the enantioselectivity (ee%) of the solid chiral catalysts [1]. The novel chiral porous materials, the chiral periodic mesoporous organosilicas (chiral PMOs), were synthesized and the relation between the porous structure and the catalytic performance of the chiral PMOs was elucidated [2]. Moreover, we developed an efficient strategy for encapsulation of transition metal complexes in the nanocage of mesoporous silicas [3]. The transition metal complexes encapsulated in the nanocages can move freely during the catalytic process because of no strong interactions between the catalysts and the solid supports. This strategy could be employed for the preparation of chiral solid catalysts with high activity and enantioselectivity owing to the cooperative activation effect. More recently, we extended the asymmetric catalysis to the nanochannels of CNT [4]. Pt nanocatalyst encapsulated inside CNTs modified by CD was found to be more active and enantioselective than Pt nanocatalyst on the outer surface of CNTs for the asymmetric hydrogenation of α‐\ketoesters, which shows the unique effect of nano‐\channels of CNTs as nanoreactors for asymmetric catalysis. The asymmetric catalysis in the nanoreactor opens an opportunity for developing novel, highly active and enantioselective heterogeneous chiral catalysts