Synthesis of new calix[4]arene based chiral ligands bearing β-amino alcohol groups and their application in asymmetric transfer hydrogenation.
Abstract
A new series of chiral calix[4]arenes bearing β-amino alcohol groups have been synthesized. The crucial steps consisted on the binding of glycidyl groups on the lower rim of the calix[4]arenes followed by their regioselective opening with amines. Those ligands were successfully tested in asymmetric transfer hydrogenation. The best results (conversion max = 97% and ee max = 87%) were obtained using calix[4]arene mono-functionalized ligands. Those results are the best ones obtained using calixarenes based ligands in asymmetric catalysis.