Novel chiral N,N′-dimethyl-1,4-piperazines with metal binding abilities

Abstract

With the objective of developing novel chiral ligands, we report an efficient strategy to prepare chiral N,N-dimethyl-1,4-piperazines, six-member heterocyclic molecules that possess metal binding features. We prepared and characterized 18 piperazines, and evaluated their ability to complex different mono- and divalent metals, using a rapid picrate extraction technique. Some newly prepared diamine ligands were used in diethylzinc alkylation of aryl aldehydes. Yields increased significantly in the presence of the diamine ligands, though enantioselectivity was low. The results demonstrate the validity of the approach for preparing and identifying useful chiral diamine ligands.