Harvesting the Strain Installed by a Paterno-Buchi Step in a Synthetically Useful Way: High-Yielding Photoprotolytic Oxametathesis in Polycyclic Systems

High-yielding one-pot photoinduced transformation of readily available endoaroyl and heteroaroyl Diels-Alder adducts into novel polycyclic aldehydes or their hemiacetals, decorated by carbo- and heterocyclic pendants, is described.