Pd-catalysed general access to 7-membered N/O-heterocyclic compounds as potential agents against inflammation.

A Pd-catalysed regioselective synthesis of 4,5-disubstituted 7-membered N/O-heterocycles was achieved via the 7-endo-dig cyclization followed by C–C bond formation of 2-(1-alkynyl)phenylacetamide. The ligand/additive free cascade reaction proceeded in the presence of PdCl2 in aqueous MeCN when the separate and individual use of methyl vinyl ketone and allyl bromide generally afforded an O- and N-heterocycle, respectively. The pharmacological assay was performed to identify the first example of a 1H-benzo[d]azepin-2(3H)-one based novel inhibitor of PDE4B.