A CuII-N,P Oxazolinylferrocene Ligand Complex for the Asymmetric [3+2] 1,3-Dipolar Cycloaddition of Azomethine Ylide with Malonates

A series of enantioselective pyrrolidine-2,4,4-tricarboxylate derivatives were synthesized by the [3+2] 1,3-dipolar cycloaddition of azomethine ylide with alkylidene malonates. By using 4mol% of a (CuN)-N-II,P oxazolinylferrocene ligand complex and 10mol% of a base, pyrrolidine analogues were obtained in high yields (77-99%) and excellent enantioselectivities (up to 99% ee).