Planar tether control groups and π-facial selectivity: Intramolecular cycloadditions for polycyclic systems

Article abstract of DOI:10.1016/S0040-4039(96)02459-8

The direct synthesis of the fused ring systems 11 (R = Me, H) and the decalin 14 are described. The use of a planar tether control group (either aromatic ring or double bond) greatly facilitates the key Diels-Alder cycloadditions. A second intermolecular cycloaddition of 14 with cyclopentadiene afforded the tetracyclic adduct 17. The interaction between the allylic ethers and diene subslituents influences the facial selectivity observed in these examples.