61647-75-4Relevant academic research and scientific papers
Iron Catalyzed Hydroformylation of Alkenes under Mild Conditions: Evidence of an Fe(II) Catalyzed Process
Pandey, Swechchha,Raj, K. Vipin,Shinde, Dinesh R.,Vanka, Kumar,Kashyap, Varchaswal,Kurungot, Sreekumar,Vinod,Chikkali, Samir H.
, p. 4430 - 4439 (2018)
Earth abundant, first row transition metals offer a cheap and sustainable alternative to the rare and precious metals. However, utilization of first row metals in catalysis requires harsh reaction conditions, suffers from limited activity, and fails to tolerate functional groups. Reported here is a highly efficient iron catalyzed hydroformylation of alkenes under mild conditions. This protocol operates at 10-30 bar syngas pressure below 100 °C, utilizes readily available ligands, and applies to an array of olefins. Thus, the iron precursor [HFe(CO)4]-[Ph3PNPPh3]+ (1) in the presence of triphenyl phosphine catalyzes the hydroformylation of 1-hexene (S2), 1-octene (S1), 1-decene (S3), 1-dodecene (S4), 1-octadecene (S5), trimethoxy(vinyl)silane (S6), trimethyl(vinyl)silane (S7), cardanol (S8), 2,3-dihydrofuran (S9), allyl malonic acid (S10), styrene (S11), 4-methylstyrene (S12), 4-iBu-styrene (S13), 4-tBu-styrene (S14), 4-methoxy styrene (S15), 4-acetoxy styrene (S16), 4-bromo styrene (S17), 4-chloro styrene (S18), 4-vinylbenzonitrile (S19), 4-vinylbenzoic acid (S20), and allyl benzene (S21) to corresponding aldehydes in good to excellent yields. Both electron donating and electron withdrawing substituents could be tolerated and excellent conversions were obtained for S11-S20. Remarkably, the addition of 1 mol % acetic acid promotes the reaction to completion within 16-24 h. Detailed mechanistic investigations revealed in situ formation of an iron-dihydride complex [H2Fe(CO)2(PPh3)2] (A) as an active catalytic species. This finding was further supported by cyclic voltammetry investigations and intermediacy of an Fe(0)-Fe(II) species was established. Combined experimental and computational investigations support the existence of an iron-dihydride as the catalyst resting state, which then follows a Fe(II) based catalytic cycle to produce aldehyde.
Some Reactions of Tris(Triphenylphosphine)-dicarbonyliron(0)
Vancheesan, S.
, p. 579 - 582 (2007/10/02)
Tris(triphenylphosphine)-dicarbonyliron(0) (I) undergoes substitution reactions with trimethylphosphite, pyridine, dimethyl sulphoxide and methylisocyanide.Substitution takes place via dissociation of I to a coordinatively unsaturated 16 electron complex, which is a highly reactive unstable intermediate.Both steric and electronic factors play a prominent role in deciding the feasibility of the reaction.Steric factor is expressed in terms of τ, the cone angle of the ligand, and electronic factor in terms of A1 mode of CO stretching frequency in Ni(CO)3L, where L is ligand for which the electronic factor is expressed in terms of νCO.Ligands with cone angle τ, greater than that of triphenylphosphine e.g. t-butylphosphine, do not react.In the reaction of I with molecular hydrogen and bromine, oxidative addition takes place.Diphenylacetylene forms two isomers, whereas carbon disulphide forms a ?-complex on reaction with I.
