Enantioselective Hydrogenation Catalyzed by Chiral Nanoporous Materials

The recent progress, particularly in this decade, in enantioselective hydrogenation using nanoporous materials supported catalysts was reviewed. The main content consists of the enantioselective hydrogenation or asymmetric transfer hydrogenation of prochiral carbonyl compounds or other prochiral substrates containing C=C or C=N double bonds using the immobilized chiral metal complex catalysts onto nanoporous materials, and the enantioselective hydrogenation of prochiral carbonyl compounds using nanoporous materials supported noble metal nanoparticles/clusters after chirally modified with cinchona alkaloids or other chiral molecules. The nanoporous materials discussed in this review involve ordered mesoporous silicates or aluminosilicates, alumina-mesoporous silica composites, nanoporous carbons, periodic mesoporous resols and metal-organic frameworks. Many examples about the enantioselective hydrogenation using nanoporous materials supported catalysts show that the enantioselectivities are similar to or even higher when compared with the corresponding homogeneous counterparts. In particular, the heterogenization of well-established soluble transition metal-based asymmetric catalysts on inorganic oxide or polymer supports allows easy separation and hence recycling and reuse of these expensive asymmetric catalysts. Nanoporous materials supported noble metal nanoparticles/clusters are also efficient in the relevant asymmetric hydrogenation reactions.