Synthesis and characterization of ‘calixsalens’: a new class of macrocyclic chiral ligands
Abstract
Template directed reaction of dialdehydes and (R,R)- or (S,S)-1,2-diaminocyclohexane affords a practical route to chiral, metal-free macrocyclic salen dimers which have a novel calixarene-like structure and show catalytic activity for enantioselective epoxidation of unfunctionalized alkenes in the presence of MnIII–NaOCl (aq.).