A stereocontrolled total synthesis of enantiomerically pure (-)-gleenl using an improved substrate to construct the spiro[4.5]decane through Claisen rearrangement has been achieved. The most striking feature of this synthesis is that the rearrangement of sterically congested dihydropyran, bearing all requisite substituents with proper stereochemistry, afforded the fully functionalized spiro[4.5]decane in a single step.