Methylenecyclopentane annulation: a synthesis of the sesquiterpenoid (±)-pentalenene
Abstract
Transformation of the readily available keto acetal (10) into the novel sesquiterpenoid (±)-pentalenene (1) is accomplished via a 12-step synthetic sequence, the key conversion [(13) into (15)] of which involves a new, recently developed methylenecyclopentane annulation process.