Interior Editing via Dynamic Molecular Recognition

The ability to engineer the interior space of molecular containers is crucial for realizing precise control over their selectivities in molecular recognition, transport, and catalysis. Despite decades of research in synthetic chemistry and materials sciences, the selective editing of chemical bonds inside molecular containers remains a formidable challenge, limiting our capacity to mimic the nanoconfined environments of bioreceptors. Here, we describe a new catalytic paradigm for activating interior chemical bonds in nanoconfined space via dynamic molecular recognition. Quinuclidine, a catalyst that can reversibly bind the cavity of α-cyclodextrin, was found to abstract hydrogen atoms selectively from one of its endo C-H bonds upon single-electron oxidation, causing the geminal hydroxyl group to flip to the interior face of the macrocycle. The endo-hydroxylated α-cyclodextrin was able to separate chiral compounds that could not be resolved by its natural counterpart in gas chromatography owing to its desymmetrized cavity and polar recognition site.