Sustainable Synthesis of Aryl and Heteroaryl Aldehydes

Aromatic aldehydes are important intermediates for the synthesis of valuable fine and specialty chemicals and many procedures for their preparation have been developed but, nowadays, most of these synthetic methods require large amounts of reagents and multiple steps, with production of wastes. In this paper, we focused on the synthesis of some (hetero)aromatic aldehydes, used either as industrial flavor/fragrances of commercial interest, such as Heliotropine®, or as key intermediates for the preparation of some APIs and of other fragrances such as Lioral® and Helional®, by reductive carbonylation of halo derivative precursors. In order to carry out an easier and more applicable process, hydrogen donors, instead of gaseous flammable and explosive hydrogen, and recyclable phosphine free low metal content catalysts, were employed.