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 H2O 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.