Pd-Catalyzed Asymmetric Synthesis of Chiral 2-Trifluoromethyl-4-(indol-3-yl)-4H-chromene Derivatives

This paper presents a new strategy for the construction of the chiral 4H-chromene skeleton. A series of chiral 2-trifluoromethyl-4-(indol-3-yl)-4H-chromenes were synthesized in moderate to good yields (60-92%) with excellent enantioselectivity (up to 97% ee) through the palladium-catalyzed asymmetric condensation of 2H-chromenes and indoles. These trifluoromethylated, stereochemically rich building blocks hold potential value in medicinal chemistry.