Synthesis of (±)-epi-Jungianol by the Gold(I)-Catalyzed Propargyl Claisen Rearrangement/Hydroarylation Cascade Reaction of Propargyl Vinyl Ethers

The synthesis of (±)-epi-jungianol was successfully carried out by the gold(I)-catalyzed propargyl Claisen rearrangement/hydroarylation cascade reaction of suitably substituted propargyl vinyl ethers as the key step to form the indane skeleton. Two routes were compared, which involved substrates with a different degree of substitution on the vinyl moiety. The one based on a propargyl vinyl ether bearing an unsubstituted vinyl moiety, despite entailing two additional steps, provided the final compound in a higher overall yield. A method for the preparation of acid sensitive propargyl vinyl ethers with an α-alkyl-substituted vinyl moiety and their reactivity under gold catalysis is also reported.