Ag‐Catalyzed Trifluoromethylative Ring Expansion of Isatins and Isatin Ketimines with Trifluorodiazoethane

A general method for the construction of trifluoromethylated 2‐quinolinones has been established herein by using a trifluoromethylative ring expansion of isatin with trifluorodiazoethane. The strategy provides a platform for the rapid synthesis of a wide range of substituted 3‐hydroxy‐4‐trifluoromethyl‐2‐quinolinones. This operationally simple and robust Ag‐catalyzed protocol successfully transforms isatin ketimines to 3‐amino‐4‐trifluoromethylquinolinones in excellent yields. The utility of this novel method is further illustrated by the conversion of the products into various synthetically and medicinally relevant molecules. An efficient Ag‐catalyzed trifluoromethylative ring expansion of isatins that enables the synthesis of 3‐hydroxy‐4‐trifluormethyl quinolinones has been achieved. The strategy readily allows access to 3‐amino‐2‐quinolinones by using isatin ketimines in place of isatins. The synthetic value of this protocol is further illustrated using various functionalization reactions of the products obtained.