3‐Acyl‐4‐hydroxypyan‐2‐ones with pendent furans, readily available from dehydroacetic acid, are substrates for intramolecular 4+4‐photocycloaddition. In the presence of stoichiometric lithium base, these substrates undergo conversion to lactone‐bridged cyclooctenones in moderate to good yields upon irradiation in THF at 0 °C. In contrast to other crossed 4+4‐photocycloadditions of pyran‐2‐ones, these examples proceed with complete diastereoselectivity for the endo cycloadducts. Readily accessible 3‐acyl‐4‐hydroxypyran‐2‐ones with pendent furans undergo 4+4‐photocycloaddition reactions in the presence of lithium ion to afford lactone‐bridged cyclooctenones with complete selectivity for the endo cycloadducts.