Gold-Catalyzed Diastereoselective Cycloisomerization of Alkylidene-Cyclopropane-Bearing 1,6-Diynes.

Treatment of 1,6-diynes (syntheses described) according to A) proceeds diastereoselectively to produce the important 1,2-trimethylenenorbornane core bearing an exocyclic alkene function. In the case of substrate (VII), the bicyclic compound (VIII) is also formed. It can be slowly converted to (IX) in the presence of the gold catalyst and is assumed to be an intermediate in the process. [ABSTRACT FROM AUTHOR]