Transition-metal-free synthesis of trifluoromethylated benzoxazines via a visible-light-promoted tandem difunctionalization of o-vinylanilides with trifluoromethylsulfinate

Abstract

9,10-Phenanthrenedione (PQ) visible-light photocatalysis for the synthesis of a series of trifluoromethylated benzoxazines in good to excellent yields has been developed by using N-(2-vinylphenyl)amides and trifluoromethylsulfinate as precursors. A plausible mechanism for the reaction is reported. It involves the oxidative difunctionalization of N-(2-vinylphenyl)amides through cascade C–O and C–C bond formation. This novel and operationally simple methodology features tolerance to diverse functional groups, is transition-metal-free and cost-effective, and can be applied in an open environment.