Homogeneous Catalysis in the Reactions of Olefinic Substances.^1a VII. Hydrogenation and Isomerization of Methyl Linoleate with Bis(triphenylphosphine)nickel Halides^1b

Novel polymer-supported β-dithioketonate nickel catalysts for selective propylene dimerization

“…Bis(tricyclohexylphosphine)nickel(II)dichloride (Ni(PCy 3 ) 2 Cl 2 ) was prepared according to the literature [14,15].…”

Nickel

“…The tetrahedral nickel complexes [NiX 2 (PPh 3 ) 2 ] (X = Cl, Br, or I) have been reported to show catalytic activity in the hydrogenation of linear, cyclic, terminal, and sterically hindered olefins; a summary of the reported activities in the hydrogenation of various substrates is provided in Table 5.1 [46][47][48][49][50]. The catalytic activity of the different halide complexes in the hydrogenation of methyl linoleate decreases in the order I > Br > Cl, but also when the iodide complex is used the activities remain extremely low, even at elevated temperatures and pressures [46].…”

“…The catalytic activity of the different halide complexes in the hydrogenation of methyl linoleate decreases in the order I > Br > Cl, but also when the iodide complex is used the activities remain extremely low, even at elevated temperatures and pressures [46]. Therefore, it was suggested that both the hydrogenation and isomerization reaction proceed via a monohydride species and that dihydrogen is activated via a heterolytic pathway [46]. Nonconjugated dienes are assumed to be converted into conjugated dienes through migration of the double bonds.…”

“…In 9), in acetic acid; entries 3, 10, 11: SCR = 5 (9 for entry 11), t = 3 h, in benzene. b) Turnover frequency in mol converted substrate per mol Ni per hour, calculated from data in [46][47][48][49][50]. c) Transannular ring closure was also observed.…”

The Oligomerization of Olefins and Related Reactions

“…Detailed attention has been given to the hydrogénation of polyunsaturated fatty acids (257,258,262,263,266,277,278; see also 348) and the course of reaction is found to depend on the nature of the catalyst. With some catalysts (e.g., Lig 2 NiX 2 ) isomerization to the conjugated system precedes hydrogénation and a trans-monosne results (258,277,278), whereas in other cases (e.g., NiCl 2 -NaBH 4 -DMF) hydrogénation occurs without initial isomerization (257,263).…”