Palladium-based innovative catalytic procedures: Designing new homogeneous and heterogeneous catalysts for the synthesis and functionalisation of N-containing heteroaromatic compounds

N-containing heteroaromatics, particularly those owning an indole or quinolone substructure, are found in numerous natural or synthetic alkaloids of biological and pharmaceutical relevance. Therefore, various synthetic methodologies have been reported to access these backbones. The most advanced procedures use transition metal catalysts, usually as soluble (homogeneous) materials. In this short review article, we report our recent developments devoted to improving current catalytic pathways toward greener processes and to designing new heterogeneous Pd-based catalysts. The latter approach brings as main advantages low metal contamination and recyclability. The potential of these developments is demonstrated through the selective synthesis, as well as the functionalisation, of (NH)-indoles, quinolones, indoxyls or stilbenes.

Figure optionsDownload high-quality image (182 K)Download as PowerPoint slideHighlights
► “On water” direct and site-selective C-H arylation of (NH)-indoles.
► Ligand and salt free heterogeneous Larock indole synthesis.
► Pd/SiO2, a simple catalyst for the one-pot synthesis of stilbenes in 1,3-propanediol.
► Carbonylative Sonogashira technology for the synthesis of 4-quinolones or indoxyls.