Cu(I)/DTBM-BIPHEP-catalyzed exo-selective 1,3-dipolar cycloaddition of azomethine ylides with cis-trifluorocrotonate for asymmetric construction of trifluoromethylated pyrrolidines

A direct and facile access to highly substituted exo-pyrrolidines bearing a unique trifluoromethyl group is developed via Cu(I)/DTBM-BIPHEP-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides with cis-4,4,4-trifluorocrotonate for the first time.