Synthesis of 5,8‐dimethoxy‐2(1H)‐quinolinones by intramolecular Wittig reaction

The title compounds 12, which are key intermediates for antitumoral diazaquinomycin A analogues, are obtained by intramolecular Wittig reaction of 1‐[3′,6′‐dimethoxy‐2′‐(α‐oxoacylamino)phenyl]alkyltriphenylphosphonium salts 11, which are prepared via lithiation of 2′,5′‐dimethoxy‐N‐pivaloylaniline 6. The applicability of this route to polysubstituted 2(1H)‐quinolinones 12 and 17 is examined.