Chiral N,N '- and N,O-bidentate anionic ligands. Preparation, metal complexation, and evaluation in the asymmetric aziridination of olefins

The chiral ligands 1-phenyl-2-[(4S)-phenyl-4,5-dihydrooxazol-2-yl]propen-2- ol (1a) and [1-phenyl-2-((4S)-phenyl-4,5-dihydrooxazol-2-yl)vinyl]-p-tolyla mine (2a) were prepared, together with some structural analogues (1b-e, 2b) in two steps from optically pure phenylglycinol or phenylalaninol. Transit ion-metal-ligand complexes were isolated from the ligand la and Cu(II), Pd( II), and Co(II). The copper complexes of la and 2a were found to be highly active catalysts for the asymmetric aziridination of styrene, giving the co rresponding N-tosylaziridine in excellent yields and with enantiomeric exce ss in the range of 15-34%.