Synthesis of Heterotriarylmethanes Catalyzed by Chiral Phosphoric Acid with 5-Aminopyrazole and Azadiene

A chiral phosphoric acid-catalyzed, efficient, operationally simple, general method for straightforward syntheses of heterotriarylmethanes employing 5-aminopyrazoles reacting with benzofurans was first reported. A wide variety of heterotriarylmethanes were obtained in good yields with excellent enantioselectivity under mild conditions. This protocol features a broad substrate scope, high functional group tolerance, and easy operation, therefore enabling late-stage functionalization. In addition, a scale-up experiment further highlighted the synthetic utility.