On-Demand Release of Secondary Amine Bases for the Activation of Catalysts and Crosslinkers

03 October 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


We demonstrate that the species present in the equilibrium of DCv ureas can be employed in reaction cascades and as triggered organocatalysts. Easily controllable stimuli like heat or addition of water shift the equilibrium towards isocyanate and free base which can function as an in situ released reagent, both catalytically and in an equimolar fashion in different reactions. While applying heat to the system leads to a reversible liberation of amine base, addition of water makes this release irreversible. We demonstrate this application of DCv ureas with two examples. Firstly, we use the liberated base to activate a protected organocatalyst for acylhydrazone formation. Secondly, this base can be employed to trigger the release of nitrile-N-oxides from chlorooximes, which can react with 4-arm PEG-acrylates to form an isoxazoline polymer gel. These findings show the utility of DCv hindered ureas beyond their application in self-healing.


Dynamic covalent chemistry
Dynamic covalent urea

Supplementary materials

DCv urea catalysis S.I. ChemRXiv
Additional experiments to support our kinetic analysis, synthesis and side reactions, as well as supplementary experimental procedures.


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