The First Syntheses of (±)-SDEF 678 Metabolite and (±)-Speciosins A–C
The epoxyquinone natural products SDEF 678 metabolite, speciosin A, speciosin B and speciosin C have been prepared for the first time via a short synthetic route based around the palladium-catalysed coupling of a halogen-substituted 1,4-benzoquinone monoketal, a Diels–Alder/retro-Diels–Alder sequence and a diastereoselective epoxidation process.