Horner-Emmons condensation of 3',5'-di(benzyloxy)acetophenone (I) with triethyl phosphonoacetate yields the unsaturated ester (II). Catalytic double bond hydrogenation in (II), with simultaneous benzyl group hydrogenolysis, leads to the substituted resorcinol (III). This is then subjected to Pechmann cyclization with ethyl 1-benzyl-3-oxopiperidine-4-carboxylate (IV) in the presence of H2SO4 and POCl3 to provide the target benzopyranopyridine compound.