A New Synthetic Approach to C2-Symmetric Octacyclic Cage Diol via Claisen Rearrangement and Ring-Closing Metathesis as Key Steps

A simple synthetic strategy to C-2-symmetric bisannulated octacyclic novel cage diol 20 is reported in eight linear steps starting with a readily available 1,4-hydroquinone 22. Here, an atom economic processes such as Claisen rearrangement, Diels-Alder reaction, intramolecular [2+2] photocycloaddition and ring-closing metathesis (RCM) were used as key steps. The synthetic approach demonstrated here opensup new opportunities to assembled highly functionalized complex cage molecules that are difficult to realize by conventional routes. The structure of the RCM product 19 was firmly established on the basis of single-crystal X-ray diffraction studies.