Asymmetric Michael Addition of Benzofuran-Derived Azadienes to 3-Fluorooxindoles Catalyzed by a Chiral Squaramide Catalyst

A highly enantioselective Michael reaction of benzofuran-derived azadienes with 3-fluorooxindoles, catalyzed by a quinine-derived squaramide catalyst, was developed. This protocol efficiently constructs a variety of 3-substituted-3-fluorooxindoles featuring two vicinal chirality centers, achieving good to high yields (68-92%) along with moderate to excellent enantioselectivities (70 to >99% ee) and diastereoselectivities (60:40 to >99:1 dr).