Acetylene monometallation

When R is hydrogen, more tautomeric forms similar to those of monometalated acetonitriles can be written . These modes appear at too low wavenumbers to be acetylenic or nitrile absorptions and therefore they were attributed to ketenimine derivatives of form R(Li)C=C=NLi. For the ionic species, Gornowicz and West proposed a delocalized structure (Scheme 8) °. Klein and Brenner called it sesquiazacetylene in a previous study . 

Monometallation of Acetylenes with a Terminal Triple Bond... 

Some reactions of terminal alkynes with monometallic species do not result in isolation of the 7i-complexed alkyne 79 but rather afford a vinylidene complex 80 wherein the acetylenic hydrogen has been transferred to the P-carbon (Scheme 4-41) [129]. This is particularly the case if the organometallic species is 16-electron or labile. In some cases isolable n-complexes... 

Trimetallic palladium and gold earbene complexes structured around a triphenylene scaffold (13) have been synthesized and used in ct-arylation of propiophenone, Suzuki-Miyaura reactions and hydroamination of acetylene. They exhibited an enhanced reactivity compared to other trimetallic as well as more conventional monometallic complexes. This enhancement is thought to arise from the specific topological properties that might favour the interaction between the catalysts and the aromatic substrates as... 

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