合成路线1

In an alternative procedure, the known hydroxynaphthalene dicarboxylate (I) is protected as the methoxymethyl ether (III) using chloromethyl methyl ether (II) and diisopropyl ethylamine. Subsequent partial hydrolysis of diester (III) with KOH leads to acid (IV). Removal of the methoxymethyl protecting group of (IV) to produce naphthol (V) is accomplished by treatment with in situ generated iodotrimethylsilane. Hydroxy acid (V) is then converted to the dioxinone derivative (VI) employing diiodomethane and CsF in hot DMF. Finally, addition of the Grignard reagent (VII) to the lactone function of (VI) yields the desired 2-ethylbutyl ketone.