Copper(i)-catalyzed asymmetric [3 + 2] cycloaddition of N-ester acylhydrazones and β-trifluoromethyl-α,β-unsaturated ketones

The first copper( i )-catalyzed asymmetric [3 + 2] cycloaddition of N -ester acylhydrazones and ketones has been developed, affording an array of chiral pyrazolidines containing a trifluoromethyl moiety bearing three vicinal stereocenters.