Investigations towards the synthesis of xylindein, a blue-green pigment from the fungus Chlorociboria aeruginosa

An approach towards the synthesis of the fungal pigment xylindein 1 is described. Synthesis of the pyranonaphthoquinone corresponding to one half of the xylindein framework is achieved over 11 steps from 1,2-epoxypentane, utilizing multiple Diels–Alder cycloaddition processes. Methods for self-coupling of dihydroxynaphthoquinones to give extended quinones are explored.