Stereoselective Total Synthesis of (±)-Labdane-8α,15-diol and (±)-Eperuane-8β,15-diol

(±)-Labdane-8α,15-diol and (±)-eperuane-8β,15-diol, diastereomeric diterpenes to each other, were prepared separately and stereoselectively, via a common 7-membered lactone from the known tricyclic keto alcohol.