Mild Regiospecific Synthesis of 1-Alkoxy-isochromenes Catalysed by Well-Defined [Silver(I)(Pc-L)] Complexes

The synthesis of 3-substituted-1-alkoxyisochromenes starting from 2-alkynylbenzaldehydes and different alcohols is reported. The reaction is catalysed by a silver(I)complex with an original macrocyclic pyridine-containing ligand (Pc-L). The approach is characterised by absolute regioselectivity, mild reaction conditions, good to excellent reaction yields, cleanness of the reaction and reduced purification steps. The reaction mechanism is investigated by in-depth 1H NMR experiments and an aimed “trapping” experiment.