Synthesis of electron-deficient ( Sa,R,R )-(CF 3 ) 2 -C 3 -TunePhos and its applications in asymmetric hydrogenation of α-iminophosphonates

Abstract A novel electron-deficient chiral diphosphine ligand bearing trifluoromethyl groups at the 6- and 6′-positions of the biphenyl backbone, ( S a ,R,R )-(CF 3 ) 2 -C 3 -TunePhos, has been synthesized from the commercially available chiral 2,4-pentanediol. The above ligand was successfully applied to palladium-catalyzed asymmetric hydrogenation of linear and cyclic α-iminophosphonates with up to 99% ee.