Catalytic asymmetric 1,3-dipolar cycloaddition reaction of nitrones with alpha'-phosphoric enones by a chiral ligand-copper(II) triflate complex

Abstract

Using the C(2)-symmetric bis-oxazoline copper(II) catalyst 6f as a chiral Lewis acid, alpha'-phosphoric enones 2 undergo 1,3-dipolar cycloaddition with nitrones 3 to provide isoxazolidines 4 with very high enantioselectivity and endo/exo selectivity.