The totalsynthesis of the Diels–Alder-type adducts (±)-kuwanol E and the heptamethyl ether derivative of (±)-kuwanon Y has been accomplished via a convergent strategy involving 2′-hydroxychalcone 6 or 9 and dehydroprenylstilbene 7, in nine steps. The synthesis features, as a key step, a Lewis acid-mediated biomimetic intermolecular Diels–Alder [4+2] cycloaddition for the construction of the cyclohexene