96095-76-0Relevant academic research and scientific papers
Study of the Reactions of Substituted Allenes with Tris(triphenylphosphine)nickel(0). An Analysis of the Factors Affecting the Regio- and Stereochemistry of ?-Complex Formation and Coupling To Form Nickelacyclopentane Complexes
Pasto, Daniel J.,Huang, Nai-Zhong,Eigenbrot, Charles W.
, p. 3160 - 3172 (1985)
The reactions of ethylallene (ETA), tert-butylallene (TBA), phenylallene (PHA), cyanoallene (CYA), and methxoyallene (MEA) with tris(triphenylphosphine)nickel(0) have been investigated and compared with the reaction of dimethylallene (DMA) with (TPP)3Ni reported earlier.At low temperatures ( PHA > MEA >> DMA > ETA > TBA.Evidence for a competitive electron-transfer process with CYA is presented.The structures of the intermediate substituted nickelacyclopentane complexes are inferred from the structures of the hydrocarbon products formed in reductive-elimination and hydrogen-migration, reductive-elimination reactions and from the structures of ketonic products formed on reaction with carbon monoxide.Specific ?-?, ?-?, and ?-? modes of coupling in syn and anti conformations of the bis-?-complexes have been identified.The regio- and stereochemistry of formation of the nickelacyclopentane ?-complexes are discussed in terms of steric and electronic (orbital energy and AO coefficients) effects in the rate-determining transition state for ?-complex formation.
