A Facile Synthesis of Bridged‐tricyclic Skeletons via Intramolecular Diels‐Alder Reaction of Cyclic 1,3‐Dienes Containing an α,β‐Unsaturated Ester

Intramolecular Diels‐Alder reaction (IMDA) precursors are easily available starting from addition of ester functionalized zinc‐copper reagents to cyclohexadienyl‐ and cycloheptadienylirontricarbonyl cation salts. The resulting cyclic 1,3‐dienes containing an α,β‐unsaturated ester functionality underwent smoothly IMDA reaction to afford bridged tricyclic compounds. Bridged heterotricyclic skeletons were also available via IMDA reaction of cyclic 1,3‐dienes bearing an imine or aldehyde functionality.