Starting from readily available cyclic homoallylic alcohols, a Prins reaction allowed the formation of a bicyclic tetrahydropyranyl carbocation intermediate that is only trapped by electron-rich aromatic rings according a further intramolecular Friedel–Crafts reaction leading to new [4.4.3]propellane structures.
Key words
Prins reaction - tetrahydropyrans - Friedel–Crafts reaction - tandem - propellanes