Gold(I) - Catalyzed Cyclizations and Enantioselective Total Synthesis of (+) - Schisanwilsonene A

Gold(I)-catalyzed activation of alkynes followed by nucleophilic attack have been extensively studied in our group. In this work, the developpement of a new reaction catalyzed by Au (I) using trimethylsilyl azide and alkynes leading to the formation of tetrazoles is first established.  Then, the  intermolecular trapping of the in situ formed Au (I)-carbenes with different novel nucleophiles is described.  Finally, the 1,5-migration reaction of 1,6-enynes catalyzed by Au (I) is applied to the synthesis of the natural products (+)-schisanwilsonene A, B and C which possess interesting biological activity against hepatitis B.