Homochiral porous metal-organic framework for highly enantioselective heterogeneous asymmetric catalysis

A homochiral porous noninterpenetrating metal-organic framework (MOF), 1, was constructed by linking infinite 1D [Cd(μ-Cl)2]n zigzag chains with axially chiral bipyridine bridging ligands containing orthogonal secondary functional groups. The secondary chiral dihydroxy groups accessible via the large open channels in 1 were utilized to generate a heterogeneous asymmetric catalyst for the addition of diethyzinc to aromatic aldehydes to afford chiral secondary alcohols at up to 93% enantiomeric excess (ee). Control experiments with dendritic aromatic aldehydes of different sizes indicate that the heterogeneous asymmetric catalyst derived from 1 is both highly active and enantioselective as a result of the creation of readily accessible, uniform active catalyst sites inside the porous MOF. Copyright © 2005 American Chemical Society.