Catalytic Ring Closing Metathesis of Dienynes: Construction of Fused Bicyclic [<b><i>n</i></b>.<b><i>m.0] Rings</i></b>

Abstract

Ruthenium carbene 1 (Cl2(PCy3)2RuCHCHCPh2) mediates the efficient and selective conversion of acyclic dienynes to fused bicyclic [n.m.0] rings containing five-, six-, and seven-membered rings. Studies with various X-substituted acetylenes (X = H, alkyls, Ph, CO2Me, SnBu3, TMS, Cl, Br, I) suggest that the dienyne metathesis is sensitive not only to these substituents but also to the catalysts employed. Among the various metal alkylidenes examined, only the ruthenium catalyst 1 exhibited metathesis activity for a range of substrates. These observations further expand the scope of catalytic RCM for the construction of complex organic compounds.