Double Capture of Difluorocarbene by 2-Aminostyrenes Enables the Construction of 3-(2,2-Difluoroethyl)-2-fluoroindoles

We report herein an efficient strategy to construct 3-(2,2-difluoroethyl)-2-fluoroindoles from activated o-aminostyrenes with ethyl bromodi-fluoroacetate as a difluorocarbene source. Through double capture of a difluorocarbene, two different types of fluorine motifs are incorporated into the products with simultaneous construction of one C–N and two C–C bonds, without the need for transition metals. This reaction features high efficiency and excellent functional group compatibility and has great potential in the late-stage modifications of pharmaceutical molecules and natural products.