Iridium complex-catalyzed reaction of 1,6-enynes: Cycloaddition and cycloisomerization

1,6-Enynes reacted with monoynes to give cyclohexadiene derivatives in the presence of a catalytic amount of (Ir(cod)CI](2)/ligand. DPPE was most suitable for cycloaddition. Diastereoselective cycloaddition was also possible. In the absence of monoynes, 1,6-enynes cycloisomerized to (2)-1-alkylidene-2-methylenecyclopentane derivatives. DPPF was most suitable for cyclolsomerization. These results are the first examples of highly Z-selective cycloisomerization.