Construction of Pyridine-Based Chiral Ionic Covalent Organic Frameworks as a Heterogeneous Catalyst for Promoting Asymmetric Henry Reactions.

The difficulties in the separation of products from the reaction mixture and the recovery of the organic cationic ionic liquids (OCILs) catalysts still need to be addressed. Post modification of the pyridine unit in the covalent organic framework (COF) via the formation of pyridinium salts with the chiral bromoacetate led to the chiral ionic COF with OCIL "immobilized", which was utilized as a heterogeneous catalyst for asymmetric Henry reactions with high yield and excellent stereoselectivity.