The alkanenitriles R(C6H5)CHCN (R = H, CH3) coordinate rapidly and quantitatively through the CN group to the complexes [Ni(PCy3)2] or [{Ni(PCy3)2}2N2]. Both the end-on [Ni(PCy3)2(σ-R′CN)] and the edge-on [Ni(PCy34)(π-R′CN)] adducts are formed,and are present in an equilibrium the position of which is governed by the amount of added PCy3. The π-complexes react to give the cyano-organometal complexes [Ni(PCy3)n(R′)(CN)] through an oxidative addition involving splitting of the CCN bond. The complexes obtained are unstable and slowly decompose under the reaction conditions to give the coupling R′-R′ (R = H) or the β-elimination R′(-H) (R = CH3) products. The kinetics of the reaction and the stereochemical result suggest a template mechanism in agreement with the findings above.
Oxidative addition of alkanenitriles to nickel(0) complexes via π-intermediates.
MORVILLO, ANTONINO;
1983
Abstract
The alkanenitriles R(C6H5)CHCN (R = H, CH3) coordinate rapidly and quantitatively through the CN group to the complexes [Ni(PCy3)2] or [{Ni(PCy3)2}2N2]. Both the end-on [Ni(PCy3)2(σ-R′CN)] and the edge-on [Ni(PCy34)(π-R′CN)] adducts are formed,and are present in an equilibrium the position of which is governed by the amount of added PCy3. The π-complexes react to give the cyano-organometal complexes [Ni(PCy3)n(R′)(CN)] through an oxidative addition involving splitting of the CCN bond. The complexes obtained are unstable and slowly decompose under the reaction conditions to give the coupling R′-R′ (R = H) or the β-elimination R′(-H) (R = CH3) products. The kinetics of the reaction and the stereochemical result suggest a template mechanism in agreement with the findings above.Pubblicazioni consigliate
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