A new synthesis of spirovetivanes via the spiro acyloin intermediate

Abstract
Ethyl-3-(1-ethoxycarbonyl-2,6-dimethylcyclohex-2-enyl)propionate 5 was stereoselectively synthesized. The diester 5 was spiroannulated by the acyloin condensation to give the bis(tri-methylsiloxy) ether 11. The ether 11 was hydrolyzed to provide the acyloins 6 and 12. The acyloins 6 and 12 were elaborated into (±)-hinesol 1, (±)-agarospirol 2, (±)-β-vetivone 3, and (±)-α-vetispirene 4.