Reactions of Unsymmetric Chiral Dialdehydes with Lysine: Regio‐ and Enantioselective Macrocyclization and Fluorescent Sensing

Abstract

Three BINOL‐based unsymmetric chiral dialdehydes, (S)‐4, (S)‐5, and (S)‐6, each containing a salicylaldehyde moiety and an ortho‐, meta‐ or para‐substituted benzaldehyde unit, are synthesized and used to react with the enantiomers of an unsymmetric chiral diamine, lysine. These reactions represent the first examples of regioselective as well as enantioselective reactions of an unsymmetric chiral dialdehyde with an unsymmetric chiral diamine to generate unsymmetric chiral macrocycles. The addition of Zn²⁺ can further enhance the selectivity for the macrocycle formation. Compounds (S)‐4 and (S)‐5 are found to exhibit chemoselective and enantioselective fluorescent recognition of lysine in the presence of Zn²⁺.