. O la 4 R= SOZPh natural produds via intramolecular cycloaddition^.^" For example, the intramolecular Diels-Alder reaction between the diene portion of a suitably substituted derivative of 1 and a dienophilic component attached to the hydroxyl group through an ester or ether linkage has been utilized in several synthetic approaches to forskolin3 as well as a total synthesis of~ latyphyllide.~ Given that the geometry of the transition state for ...
