Heterogeneous Palladium Catalysts for a New One-Pot Chemical Route in the Synthesis of Fragrances Based on the Heck Reaction

The one‐pot synthesis of the fragrance 4‐(p‐methoxyphenyl)butan‐2‐one, with raspberry scent, has been carried out using palladium on different supports such as magnesium oxide (MgO), hydrotalcite, hydroxyapatite (HA), aluminium oxide (γ‐Al2O3) and titanium dioxide (TiO2). The first pathway consists of a Heck coupling between 4‐methoxyiodoanisole and methyl vinyl ketone followed by hydrogenation. Palladium supported on titanium dioxide showed the best performance for carrying out both consecutive steps giving 4‐(p‐methoxyphenyl)butan‐2‐one with high yields and selectivity. The Pd‐TiO2 catalyst is more active than a homogeneous palladium complex that is well accepted in the literature as being highly active for performing Heck reactions.