Vinyl Ruthenium Carbenes: Valuable Intermediates in Catalysis

Abstract

Vinyl ruthenium carbenes are easily prepared from the neutral Ru(II) complex Cp*RuCl(cod) in the presence of functionalized alkynes and diazoalkanes. These intermediates have been proposed for several transformations in which the nature of the products are strongly dependent of the functionality on the alkyne sub-stituents. New modes of catalytic cyclizations due to the electrophilicity of these vinyl ruthenium carbene intermediates are presented in this chapter. Alkynyl ace-tals, ethers and amines gave rise to complex bicyclic structures, spiro- and fused, in an intramolecular redox, neutral process that involved [1,n]-hydrogen transfers/cy-clization. New catalytic heterocyclizations have been also achieved by trapping the in situ generated vinyl ruthenium carbenes with O- and N-nucleophiles from alkyn-als/alkynones and alkynylamines.