One‐Pot Synthesis of Furo‐ or Thienoquinolines through Sequential Imination and Intramolecular Palladium‐Catalyzed Direct Arylation

The sequential imination and intramolecular palladium‐catalyzed direct arylation of thiophene‐3‐carbaldehyde or furan‐3‐carbaldehyde with 2‐haloanilines provided a one‐pot access to furo‐ or thienoquinolines in high yields with H 2 O and HBr as the major waste. Both electron‐withdrawing and ‐donating substituents on the 2‐haloaniline derivatives were tolerated. These furo‐ or thienoquinoline derivatives can be employed in the direct arylation at C‐5 of the furyl or thienyl moiety, and a variety of corresponding arylation products were obtained in high yields.