AI Article Synopsis
- - Macrocycles are important structures in creating catalysts, drugs, and complex molecular assemblies, but producing them efficiently has been a challenge due to low yields in past methods.
- - This study introduces a new method using dynamic hindered urea bonds (HUB) to create urea macrocycles with high efficiency and near-quantitative yields by mixing diisocyanate and hindered diamine at high concentrations.
- - The presence of bulky N-tert-butyl groups is crucial, as they enhance both the formation and stabilization of these macrocycles, and can be removed with acid to solidify the final structure.
Article Abstract
Macrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles in high yield under high reaction concentrations are rare. Here we report the use of dynamic hindered urea bond (HUB) for the construction of urea macrocycles with very high efficiency. Mixing of equal molar diisocyanate and hindered diamine leads to formation of macrocycles with discrete structures in nearly quantitative yields under high concentration of reactants. The bulky N-tert-butyl plays key roles to facilitate the formation of macrocycles, providing not only the kinetic control due to the formation of the cyclization-promoting cis C = O/tert-butyl conformation, but also possibly the thermodynamic stabilization of macrocycles with weak association interactions. The bulky N-tert-butyl can be readily removed by acid to eliminate the dynamicity of HUB and stabilize the macrocycle structures.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7947004 | PMC |
| http://dx.doi.org/10.1038/s41467-021-21678-3 | DOI Listing |
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