Highly diastereoselective synthesis of decalin skeletons with quaternary carbon centers via the tandem oxy-Cope/ene/Claisen reaction.

The highly diastereoselective cascade sequence of three successive thermal pericyclic reactions of 1,2-divinylcyclohexanol allyl and propargyl ethers is described. This novel tandem process provides an efficient synthesis of sesqui- and diterpenoid skeletons having a quaternary carbon at C9. [reaction: see text]