Tandem synthesis of dihydronaphthalen-1(2)-one derivatives aldol condensation-Diels-Alder-aromatization sequence of reactions.

A new series of dihydronaphthalen-1(2)-one derivatives were synthesized in high yields starting from commercially available 3,5,5-trimethylcyclohex-2-en-1-one 1a, aromatic aldehydes 2, and diethyl acetylenedicarboxylate. Reaction of 1a with the aldehydes produced the respective dienones 3, which could cycloadd to dialkyl acetylenedicarboxylate, either stepwise or , under aqueous/organocatalyzed (DMAP) conditions. The respective adducts 4, were produced efficiently a Diels-Alder-double bond isomerization-oxidative aromatization sequence and were characterized based on the analysis of their H and C NMR spectra.