Torand Synthesis by Trimerization—New Receptors for Guanidinium

The largest cycloarene derivative reported so far, the torand 1, is surprisingly readily accessible by CsOH-mediated cyclotrimerization. According to Macromodel calculations, 1 is almost planar and binds guanidinium with formation of six almost ideal hydrogen bonds with only slight change in conformation: the UV spectra of the torand and of its guanidinium complex are almost identical.