Merging Imidazolidines with a Trifluoromethylated Tetrasubstituted Carbon through Tungsten Catalyzed 1,3-Dipolar Cycloaddition.

An unprecedented 1,3-dipole cycloaddition between acyclic CF3-ketimines and N-benzyl azomethine ylide has been allowed by tungsten catalysis, furnishing a range of novel imidazolidines bearing a trifluoromethylated tetrasubstituted carbon center. This reaction appears as one of rare examples that challenging acyclic CF3-ketimines have been engaged in 1,3-cycloaddition reactions. The capability for gram-scale synthesis and variant derivatizations of cycloaddition adducts illustrates the synthetic potential of this approach. This protocol provides a facile access to a rapidly enlarging pool of motifs with a trifluoromethylated fully substituted carbon.