SYNTHESIS AND CHARACTERIZATION OF CHIRAL CU(I) COMPLEXES OF SUBSTITUTED PYRROLIDINE LIGANDS - EFFICIENT CATALYSTS FOR CYCLOPROPANATION REACTIONS

A series of new copper(I) complexes of chiral bidentate N,N'-ligands ( (S)-2-t-butylaminocarbonylpyrrolidine (1), (S)-1,2-(bis-t-butylaminoca rbonyl)pyrrolidine (2), inocarbonyl-2-(1-naphthylaminocarbonyl)pyrroli dine (3), laminocarbonyl-2(1-naphthylaminomethyl)pyrrolidine (4), -1,2 -(bis-t-butylaminocarbonyl)-4-aminopyrrolidine (5)) of general formula [Cu(CH3CN) (L-L)]X (X=PF6, ClO4) have been synthesised and fully char acterised by elemental analysis, IR, electronic and NMR spectroscopy. These complexes catalyse the cyclopropanation of styrene, used as a mo del for monosubstituted olefins, with ethyl diazoacetate to yield a mi xture of cis/trans ethyl 2-phenylcyclopropan-1-carboxylates with up to 30% ee.