Highly stereoselective biomimetic polyene cyclizations using chiral pentadienol tricarbonyliron complexes

Acyclic E-5,9-polyenes linked to chiral 1-pentadienol tricarbonyliron fragments are highly stereoselectively cyclized via cationic intermediates with retention of configuration in chair-like transition states (several X-ray structures). This allows the preparation of diastereomerically pure trans-decalinic diene complexes, from which chiral bicyclic sesquiterpenes and tricyclic diterpenes can be synthesized.