Synthesis of novel chiral oxazoline ligands and application in the highly enantioselective diethylzinc addition to N-diphenylphosphinoylimines

Abstract: Two sets of novel chiral oxazoline ligands were designed and conveniently prepared from readily available l-aspartic acid and evaluated in enantioselective diethylzinc addition to N-diphenylphosphinoyl imines. In the presence of stoichiometric amounts of these ligands, high enantioselectivities (up to 95% ee) and yields (up to 85%) were achieved for several aromatic imines in toluene at room temperature. Furthermore, the effect of the structure of the ligand on the reaction was studied. [Copyright &y& Elsevier]