Synthesis of Indole/Benzofuran-Containing Diarylmethanes through Palladium-Catalyzed Reaction of Indolylmethyl or Benzofuranylmethyl Acetates with Boronic Acids

The palladium-catalyzed synthesis of indole/benzofuran-containing diarylmethanes starting from indolylmethyl or benzofuranylmethyl acetates with boronic acids has been investigated. The success of the reaction is influenced by the choice of precatalyst: with indolylmethyl acetates the reaction works well with [Pd(eta (3) -C (3) H (5) )Cl] (2) /XPhos while with benzofuranylmethyl acetates Pd (2) (dba) (3) /XPhos is more efficient. The good to high yields and the simplicity of the experimental procedure make this protocol a versatile synthetic tool for the preparation of 2- and 3-substituted indoles and 2-benzo[ b ]furans. The methodology can be advantageously extended to the preparation of a key precursor of Zafirlukast.

Automated summary

The palladium-catalyzed synthesis of indole/benzofuran-containing diarylmethanes was investigated, showing that the choice of precatalyst is crucial for the success of the reaction. Different precatalysts were found to be more efficient for different substrates, leading to good to high yields. This methodology can be extended to the preparation of a key precursor of Zafirlukast.