An Expeditious Nazarov Cyclization Strategy toward the Hydroazulene Core of Guanacastepene A

(Matrix presented) The hydroazulene core of guanacastepene A has been synthesized in five steps from commercially available starting materials using a classical Nazarov cyclization to install the stereochemistry in the cyclopentanone diastereoselectively. In the presence or absence of Lewis bases, a hydroazulenone or a spirocyclic ketone generated via a novel Wagner-Meerwein rearrangement is obtained with excellent selectivity and yield.link_to_subscribed_fulltex