Fe-BPsalan complex-catalyzed asymmetric 1,3-dipolar [3 + 2] cycloaddition reaction of N,N′-cyclic azomethine imines with α,β-unsaturated acyl imidazoles

A practical iron-catalyzed asymmetric 1,3-dipolar cycloaddition of N , N ′-cyclic azomethine imines with α,β-unsaturated acyl imidazoles was developed to afford N , N ′-bicyclic pyrazolidine in good yields and excellent stereoselectivities (up to 98% ee).