Pillarureaarenes: Urea-Embedded Pillararenes for Amino Acid Derivative Recognition

A three-dimensional pillarureaarene (P3U6A) was synthesized via fragment-coupling cyclization of dialkoxybenzene and urea units. Single-crystal analysis revealed a shield-shaped structure stabilized by intramolecular hydrogen bonds. The macrocycle demonstrated strong binding with phenylalanine ethyl ester salts. Further derivatization gave P3EU6A, showing chiral recognition of a series of amino acid derivatives via induced circular dichroism (CD). This work introduces a versatile platform for constructing urea-embedded pillararenes with potential applications in host–guest chemistry and chirality sensing.