Synthesis of a Spirovetivane Synthon

The spiravetivane sesquiterpenes are characterized by a Spiro [4.5]decane ring system. Illustrative are the essenti oil component β-betiv ne (1) and the antifungal metabolite lubimin (2).² As part of a structural problem arising from our investigations of plant anticancer constituents¹we developed a synthesis of the potential spirovetivane synthon 10. The very workable synthesis (5- > 10) of ketone 10 described below should prove useful in approaches to certair spirovetivanes with a 1,4 oxygen-carbon to spiro-carbon relationship. Initially efforts were directed at utilizing the Plattner³ malonic ester and Dieckmann cyclization₄ approach (3- > 4) to ketone 7. The Singh⁴ route to ester 4.