Homochiral Crystallization of Metal-Organic Silver Frameworks: Asymmetric [3+2] Cycloaddition of an Azomethine Ylide

摘要

Metal-organic frameworks (MOFs) are hybrid solids with infinite network structures built from organic bridging ligands and inorganic connecting nodes. Besides the potential applications in many diverse areas, MOFs are ideally suited for catalytic conversions, because they can impose size- and form-selective restriction through readily fine-tuned channels and pores, thus providing precise knowledge about the pore structure and the nature and distribution of catalytically active sites. In particular, analogues of homogeneous asymmetric catalysts can be synthetically incorporated into MOFs, thus resulting in the incorporation of the selectivity of these single-site catalysts into micropores, and thereby enhancing the shape-, size-, and enantioselectivities of catalytic reactions in comparison to those performed in homogeneous solution. While recent progress in MOF-based asymmetric catalysis has proved that these emerging catalysts provide a new exciting opportunity for the synthesis of enantiopure compounds, including chiral drugs and fine chemicals, privileged asymmetric metal catalysts or organocatalysts that are incorporated into the nodes of frameworks are still quite limited.