Reducing rotatable bonds in one substrate accelerates a bimolecular Diels-Alder reaction in a bis-calix[4]pyrrole
Jiaming Huang1, Marta Martínez-Belmonte2, Pablo Ballester1,3
1Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), 43007 Tarragona, Spain. pballester@iciq.es.
Abstract:
We report the quantitative self-assembly of an endohedrally functionalized octa-imine cage from two calix[4]pyrrole scaffolds via dynamic covalent chemistry. The cavity combines size and shape complementarity with enzyme-like directional guest binding. Acting as a molecular flask, the cage stereoselectively promotes a bimolecular Diels-Alder reaction, shifting the equilibrium toward the product. Restricting substrate rotation enhanced the reaction rate dramatically (kincluded/kbulk ≈ 600 M).
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