Multicomponent Assembly of High‐Component Covalent Organic Cages

Multicomponent reactions (MCRs), a powerful strategy for generating desired products by employing more than two starting materials in one-pot reactions, have been determined to be a superior synthetic strategy to achieve structural complexity and functional diversity. However, the use of MCRs in fabricating the multicomponent covalent organic cages (MCOCs) is still in its infancy. Here we report coronavirus-shaped MCOCs, formed by MCR involving a Schiff-base reaction (C═N bonds), coupled with the formation of dative B←N and B─O bonds. Specifically, reaction of bowl-shaped tetraformylcalix[4]resorcinarene, linear heteroditopic amino-substituted phenylboronic acid, and spike alcohol synthons can afford [6+24+24] MCOCs with a large octahedral cavity, 8 triangle windows, 12 rhombic windows, and 24 functional alcohols, as determined by single crystal X-ray crystallographic analysis. Notably, the number of components for the MCOCs reaches up to 54, making them the highest in covalent organic cages. Such MCR self-assembly can also afford MCOCs other sizes and topologies just using amino-substituted phenylboronic acid synthons with different lengths and angles. Interestingly, the MCOCs can be functionalized by alcohols with different substituent groups via both one-pot reaction and post-synthetic modification methods for desired properties. This work emphasizes the utilization of MCRs in constructing functional high-component organic cages with desired properties.