Novel C 2-symmetric chiral O, N, N, O-tetradentate 2, 2-bipyridyldiolpropane ligands: synthesis and application in asymmetric diethylzinc addition to aldehydes
Abstract First synthesis of C 2-symmetric chiral O, N, N, O-tetradentate 2, 2- bipyridyldiolpropane ligands is described. The Mukaiyama–Michael reaction was applied as an important reaction for the synthesis of 2, 2-bipyridylpropane 9. Among the ligands synthesized, ligand 11 exhibits excellent chiral induction (up to 97% ee) in diethylzinc addition to various aldehydes. The use of additional Lewis acid such as Ti (O i Pr) 4 in ...