Preparation of Polymer-supported Chiral 1,2-Diamines and Their Application to Asymmetric Reaction

Recent development of asymmetric synthesis is strongly dependent on the design of the chiral ligand molecule. Numbers of chiral catalysts and reagents have skillfully incorporated the enantiopure 1, 2-diamines and their derivatives into their chiral ligand structure. Studies of polymer-supported chiral ligands are always important mainly due to their recyclability. Although 1, 2-diamines have been efficient chiral ligand, the polymer-supported version has not been studied. In this context we concentrated on the preparation of optically active 1, 2-diamine which could be immobilized to polymer. New chiral 1, 2-diamine having phenolic OH groups was synthesized and attached to Merrifield type resins. Another way to obtain polymeric chiral 1, 2-diamine is polymerization of the corresponding chiral 1, 2-diamine monomer. These chiral 1, 2-diamine polymers were used as chiral ligand of the catalyst for asymmetric hydrogenation of aromatic ketones to yield the alcohols with high level of enantioselectivities. These results opened the possibility of a new synthetic methodology in asymmetric reactions using polymeric chiral 1, 2-diamine ligand.