Ethyl phosphite, nickel complexes

Ethylene hydrocyanation by [Ni P(0-o-tolyl)3 4] follows the cycle of Eq. 9.20. Oxidative addition of HCN to the metal gives a 16e nickel hydride that undergoes ethylene insertion to give an ethyl complex, followed by reductive elimination to give the EtCN product. The reaction with butadiene is more complex but goes by a closely related route not discussed in detail here. The best ligands are bulky, ir-acceptor P-donors, such as tri-o-tolyl phosphite. 

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