[4 + 2] Annulation of CF ₃ -π-Allyl–Pd Species with Isatic Acids for Direct Access to 3-Trifluoroethyl-4-carboxylate Quinolines

Herein, we report a catalytic [4 + 2] annulation between trifluoromethyl allyl carbonates and isatic acids that provides direct access to 3-trifluoroethyl-4-carboxylate quinolines. The transformation proceeds smoothly under mild conditions and accommodates a broad range of electron-donating, electron-withdrawing, and sterically demanding substituents. In addition, a one-pot protocol enables efficient conversion of the annulation products into 3-trifluoroethyl-4-amido quinolines under the same reaction conditions. The synthetic versatility of this strategy is further demonstrated through the one-pot preparation of a trifluoroethyl analogue of brequinar, as well as the streamlined synthesis of trifluoroethylated analogues of bioactive scaffolds.