CO and H2 gas-free efficient reductive carbonylation of aryl iodides. Use of smart recyclable metal-based catalysts

In this paper, we studied an efficient protocol of reductive carbonylation two aryl iodides, namely 2-iodo-5-ethylthiofene and 5-iodobenzo[d][1,3] dioxole, employing formic acid, propylphosphonic anhydride (T3P) a base, to afford aldehydes used as such industrial flavors/fragrances or key intermediates for some APIs other fragrances. Our approach, comparing the previously described [1], not only avoids use unsafe reagents and/or solvents but, noteworthy, uses easily prepared heterogeneous catalysts with low content metal(s), 0.3 % Pd/Al2O3, (0.18 Pd, 0.44 Cu)/Al2O3 1 Cu/Al2O3. These catalysts, well commercial Pd/C species tested here comparison, are also recyclable have been characterized before after by FE-SEM, EDS TEM spectroscopy. Noteworthy, both bimetallic system Pd-Cu/Al2O3, containing very amount expensive palladium %) Cu/Al2O3, no at all, showed high activities.