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

Abstract

A new series of dihydronaphthalen-1(2H)-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 in situ, under aqueous/organocatalyzed (DMAP) conditions. The respective adducts 4, were produced efficiently via a Diels–Alder-double bond isomerization-oxidative aromatization sequence and were characterized based on the analysis of their ¹H and ¹³C NMR spectra.