1,1′-Dialkynylferrocenes as Substrates for Bidirectional Alkyne Metathesis Reaction

In the construction of ferrocene-based molecular wires, alkyne metathesis was investigated as an alternative to palladium-catalyzed coupling reactions for the synthesis of alkynyl ferrocenes. With a Mortreux catalyst system [Mo(CO)(6), 4-chloro- or 2-fluorophenol], (1-propynyl) ferrocenes gave the expected homo metathesis products in moderate yields. Because the Mortreux catalyst system is not compatible with 1,1'-dialkynylferrocenes, a nitridomolybdenum catalyst introduced by Furstner was tested in bidirectional homo and cross-alkyne metathesis reactions. Although the homo alkyne metathesis products were obtained in poor yields, the cross-alkyne metathesis reactions afforded the expected products in good overall yields.