Multicomponent Click Reaction: The Concept And Its Application In Polymer Chemistry

‘Old’ reactions may give out light again if we look back to them from new aspects.The raise of the click chemistry gave these ‘old’ reactions new name,click reaction,and new vitality.Click reactions are then widely used in many research fields,and help researchers solve problems easily and efficiently,which promotes the development of chemistry.During our study of multicomponent reactions(MCRs),we are excited to find a well-known MCR,the Ugi reaction,is another possible click reaction,but with more diversities and rich functionalities.In this thesis,we introduced this ‘old’ reaction into polymer chemistry,illustrating it as a new ‘click’ reaction,namely the multicomponent click(MCC)reaction,and we applied it into several research fields to provide new strategies to solve problems.Firstly,the Ugi reaction was used in polymer conjugation to prepare a series of mid-functional block copolymers.The Ugi reaction could couple two polymer chains together highly efficiently under benign condition just like click reactions.Meanwhile,due to its unique multicomponent nature,the Ugi reaction could facilely implant new functions to the products to get mid-functional block copolymers.Thus,the Ugi reaction might be considered as a MCC reaction.Secondly,the Ugi reaction had been applied in the field of protein modification as a reliable method to synthesize a series of multifunctional PEGylation agents.And those PEG derivatives were successfully conjugated on protein surface to generate corresponding multifunctional protein-polymer conjugates.Compared to traditional PEGylation technology,the method using MCC reaction incorporates new functions to the PEG derivatives and subsequent protein-polymer conjugates,demonstrating its potential to prepare the third-generation PEGlytion agents.Thirdly,a facile one-pot Ugi-RAFT system had been constructed to easily prepare well-controlled polymers with multi-functional groups at the chain end.The strategy might have potential to synthesize new functional polymers for multipurpose applications in different areas.Last but not least,Ugi reaction has been successfully introduced into material science as a MCC reaction to collaborate with π-π stacking and RAFT polymerization in a one-pot system,resulting in the successful surface modification of carbon nanotubes(CNTs)with(co)polymers.According to the click features and applications in these fields,the Ugi reaction could be called a MCC reaction.And we expect this new kind of click reactions may enlarge the members of click chemistry family and promote the development of chemistry.