Au(I)-Catalyzed Cyclization of Enynes Bearing an Olefinic Cycle

Gold(I)-catalyzed cyclization of enynes containing an olefinic cycle has been studied. The introduction of an olefinic ring instead of a terminal alkene in enynes dramatically increased the yield of the reaction. Enynes having an olefinic cycle were prepared by a rhodium-catalyzed intermolecular [4 + 2] cycloaddition of diynes with butadiene. Consecutive rhodium-catalyzed Diels−Alder/gold(I)-catalyzed cycloisomerization reactions were integrated in a one-pot reaction.