A Glycerol‐Based Deep Eutectic Solvent as Natural Medium and Organic Reductant for Homocoupling of (Hetero)Aryl Chlorides: a Green Route to 2,2’‐Bipyridine and Biaryl Scaffolds
Andrea Nicola Paparella, Francesco Messa, Giuseppe Dilauro, Luigino Troisi, Serena Perrone, Antonio Salomone
Abstract
Abstract A glycerol‐based Deep Eutectic Solvent (DES) enables the Pd‐catalyzed activation of (hetero)arylchlorides and promotes the formation of 2,2’‐bipiyridines and biaryls through an Ullmann‐type homocoupling in smooth experimental conditions (80 °C) with Ca(OH) 2 as a green base and Pd/C as heterogeneous catalyst. Noteworthy, the coupling does not need the addition of external reducing agents, like metals, since the glycerol present in the DES acts as a safe and green organic reductant. The heterogeneous catalytic system (DES‐Pd/C) showed to be easily recyclable and has been applied to the sustainable synthesis of the Abametapir drug.