Atropisomer-based construction of macrocyclic hosts that selectively recognize tryptophan from standard amino acids

A syn-atropisomer of naphthalene diimide as a highly preorganized precursor was used to construct a type of trapezoid-shape macrocycle, namely 'trapezoid' molecular boxes (TBox). As supramolecular hosts, TBox can bind electron-rich guests and selectively recognize free tryptophan and tryptophanyl residues from 20 standard amino acids.