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A newly developed Ming-Phos ligand with a 3,5-bis(trifluoromethyl)phenyl substituent was demonstrated to be highly efficient for Ag-catalyzed asymmetric [3 + 2] cycloaddition reactions of azomethine ylides with maleimides, cyclopentene-1,3-diones, and N-(2-t-butylphenyl)maleimide. Being easily prepared on the gram scale in one step, the ligand in combination with a Ag catalyst enables the synthesis of a variety of highly functionalized bicyclic pyrrolidine derivatives in good yields and excellent enantioselectivities under mild conditions.

The employment of β,β-disubstituted enones as dipolarophiles poses a considerable challenge due to their steric hindrance and low reactivity. A copper-catalyzed asymmetric exo-selective dipolar cycloaddition of β-trifluoromethyl β,β-disubstituted enones with azomethine ylides was developed, which provides an efficient access to valuable pyrrolidines bearing a trifluoromethylated all-carbon quaternary stereocenter. Up to quantitative yields with up to >20 : 1 dr and 99% ee were delivered. A broad substrate scope, good functional group tolerance, high stereoselectivity, as well as diverse synthetically valuable transformations of the products make this approach highly attractive.

The enantioselective intermolecular [2 + 2] cycloaddition of 3-styrylindoles with N-allenyl oxazolidinone has been achieved for the first time by the employment of a Xiang-Phos derived chiral gold-catalyst. The corresponding cycloadducts could be obtained in good yields (up to 95%) with up to 95% ee.