Alkali-Cation-Selective\nArylation Promoted by Ion\nRecognition of Foldamers

To explore alkali-cation selectivity at the chemical\nreaction level,\nin this work, we for the first time focused on the different behaviors\nof potassium and sodium ions in intra- and intermolecular arylation.\nWe prepared a series of aromatic foldamers based on pyridine/oxadiazole\nalternating sequences as the catalysts for the arylation. Our studies\nrevealed that foldamers can selectively recognize K<sup>+</sup> over\nNa<sup>+</sup> and the interactions between foldamers and K<sup>+</sup> drive the arylation with a significant yield. In contrast, no trace\nof the product can be found with Na<sup>+</sup>. Furthermore, foldamers,\nwith biased handedness, can afford products with optical activity.\nThe balance between two enantiomers of products can be freely controlled\nby the different conformations of foldamers.