Abstract Several dienynes bearing different substituents have been synthesized and subjected to a ring-closing metathesis (RCM) reaction using ruthenium carbene complexes. Dienynes containing a pre-existing ring and a quaternary center attached to the alkyne give the expected tandem metathesis products in high yields. For these substrates, a high selectivity for different ring sizes was achieved by modifying the reactivity of one alkene. In ...
