73424-08-5Relevant academic research and scientific papers
Interplay of bite angle and cone angle effects. A comparison between o-C6H4(CH2PR2)(PR′ 2) and o-C6H4(CH2PR 2)(CH2PR′2) as ligands for Pd-catalysed ethene hydromethoxycarbonylation
Fanjul, Tamara,Eastham, Graham,Floure, Joelle,Forrest, Sebastian J. K.,Haddow, Mairi F.,Hamilton, Alex,Pringle, Paul G.,Orpen, A. Guy,Waugh, Mark
, p. 100 - 115 (2013/02/22)
The following unsymmetrical diphosphines have been prepared: o-C 6H4(CH2PtBu2)(PR 2) where R = PtBu2 (L3a); PCg (L3b); PPh2 (L3c); P(o-C6H 4CH3)2 (L3d); P(o-C 6H4OCH3)2 (L3e) and o-C6H4(CH2PCg)(PCg) (L3f) where PCg is 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl. Hydromethoxycarbonylation of ethene under commercially relevant conditions has been investigated in the presence of Pd complexes of each of the ligands L 3a-f and the results compared with those obtained with the commercially used o-C6H4(CH2P tBu2)2 (L1a). The Pd complexes of the bulkiest ligands L3a, L3b and L3f are highly active catalysts but the Pd complexes of L3c, L3d and L3e are completely inactive. The crystal structures of the complexes [PtCl2(L1a)] (1a) and [PtCl2(L 3a)] (2a) have been determined and show that the crystallographic bite angles and cone angles are greater for L1a than L3a. Solution NMR studies show that the seven-membered chelate in 1a is more rigid than the six-membered chelate in 2a. Treatment of [PtCl(CH3)(cod)] with L3a-f gave [PtCl(CH3)(L3a-f)] as mixtures of 2 isomers 3a-f and 4a-f. The ratio of the products 4:3 ranges from 100:1 to 1:20, the precise proportion is apparently governed by a balance of two competing factors, steric bulk and the antisymbiotic effect. The palladium complexes [PdCl(CH3)(L3b)] (5b/6b) and [PdCl(CH 3)(L3c)] (5c/6c) react with labelled 13CO to give the corresponding acyl species [PdCl(13COCH3)(L 3b)] (7b/8b) and [PdCl(13COCH3)(L 3c)] (7c/8c). Treatment of [PdCl(13COCH3)(L)] with MeOH gave CH313COOMe rapidly when L = L3b but very slowly when L = L3c paralleling the contrasting catalytic activity of the Pd complexes of these two ligands. The Royal Society of Chemistry 2013.
Catalyst activity and selectivity in the isomerising alkoxycarbonylation of methyl oleate
Christl, Josefine T.,Roesle, Philipp,Stempfle, Florian,Wucher, Philipp,Goettker-Schnetmann, Inigo,Mueller, Gerhard,Mecking, Stefan
supporting information, p. 17131 - 17140 (2014/01/06)
The synthesis of unsymmetrical diphosphine ligands (3 a-g) with an o-tolyl backbone and tert-butyl, adamantyl, cyclohexyl and isopropyl substituents on the phosphorus moiety is described (1,2-(CH2PR2) (PR′2)C6H
Synthesis and reactivity of o-benzylphosphino- and o-α- methylbenzyl(N, N-dimethyl)amine-boranes
Heiden, Zachariah M.,Schedler, Michael,Stephan, Douglas W.
experimental part, p. 1470 - 1479 (2011/04/23)
The series of o-benzylphosphino-boranes, o-(R2B)C 6H4CH2PtBu2 (R = Cl 3, Ph 4, Cy 6, C6F5 7, Mes 8) and o-(BBN)C6H 4CH2PtBu2 (5), were synthesized from reactions of the respective chloroboranes with the lithiated benzyl-phosphine. In an analogous fashion, the α-methylbenzyl(N,N-dimethyl)amine-boranes o-(R 2B)C6H4CH(Me)NMe2 (R = Cl 10, Ph 11, Cy 12, C6F5 13, Mes 14) were prepared. While these species were inactive in the catalytic hydrogenation of tBuN≡CHPh, compounds 7, 8, and 14 did react with H2 at elevated temperatures (100 °C), resulting in the elimination of HC6F5 and mesitylene, respectively. In the latter case, the species o-((Mes)HB)C 6H4CH(Me)NMe2 15 was isolated. 14 was also shown to react with H2O to give the species o-((Mes)(HO)B)C 6H4CH(Me)NMe2 16 with the loss of mesitylene. The structure of these compounds and the nature of these reactions were also probed spectroscopically, crystallographically, and computationally. The energies for the products of hydrogenation, the phosphonium and ammonium hydridoborates, were computed. In all cases, these products were endothermic with respect to the precursor phosphine-boranes and amine-boranes and H 2. The barriers to H2 activation were found to be in the range of 24-38 kcal/mol. These theoretical studies also demonstrate that the steric bulk around the boron center dramatically affects the activation barrier for H2 activation, while the Lewis acidity of the borane has the largest effect on the stabilization of the resulting onium-borohydride. In the case of the elimination reactions, the driving forces appear to be the loss of arene byproduct and formation of a strong donor-acceptor bond.
PROCESS FOR THE CARBONYLATION OF A CONJUGATED DIENE
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Page 29; 30, (2010/02/09)
A process for the carbonylation of a conjugated diene, comprising reacting the conjugated diene with carbon monoxide and a co-reactant having a mobile hydrogen atom in the presence of a catalyst system including: (a) a source of palladium; and (b) a bidentate diphosphine ligand of formula (II): R1R2 > p1R3m-R-R4n-p2 5R6 wherein p1 and p2 represent phosphorus atoms; R1, R2, R5, and R6 independently represent the same or different optionally substituted organic radical containing a tertiary carbon atom through which each radical is linked to the phosphorus atom; R3 and R4 independently represent the same or different optionally substituted methylene groups; R represents an organic group comprising the bivalent bridging group C1-C2 through which R is connected to R3 and R4; m and n independently represent a natural number in the range of from 0 to 4, wherein the rotation about the bond between the carbon atoms C1 and C2 of the bridging group is restricted a temperature in the range of from 0 °C to 250 °C, and wherein the dihedral angle between the plane occupied by the three atom sequence composed of C1, C2 and the atom directly bonded to C1 in the direction of p1, and the plane occupied by the three atom sequence C1, C2 and the atom directly bonded to C2 in the direction of p2, is in the range of from 0 to 120°; and (c) a source of an anion.
