An efficient continuous flow approach to furnish furan-based biaryls

Abstract

Suzuki cross-couplings of 5-formyl-2-furanylboronic acid with activated or neutral aryl bromides were performed under continuous flow conditions in the presence of (Bu)₄N⁺F⁻ and the immobilised t-butyl based palladium catalyst CatCart™ FC1032™. Deactivated aryl bromides and activated aryl chlorides were cross-coupled with 5-formyl-2-furanylboronic in the presence of (Bu)₄N⁺OAc⁻ using the bis-triphenylphosphine CatCart™ PdCl₂(PPh₃)₂-DVB. Initial evidence indicates the latter method may serve as a universal approach to conduct Suzuki cross-couplings with the protocol successfully employed in the synthesis of the current gold standard Hedgehog pathway inhibitor LDE225.