Hydrogenation catalytique homogene a l'aide de complexes rhodium—diphosphines

Poulin, Jean-Claude; Dang, T. P.; Kagan, Henri B.

doi:10.1016/s0022-328x(00)88777-x

Cited by 42 publications

(9 citation statements)

References 9 publications

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“…the C-H reductive elimination step as well as the H 2 oxidative addition step) appear to increase with increasing chelate ring size. A general trend of increasing overall catalytic rate with increasing diphosphine chelate ring size also has been noted by Kagan et al 9 In this contribution we report a comparison of the performance of directly analogous heterodiphos systems with a P(C) n OP backbone (n = 1-4) that has not been made before. In addition, we describe full results about the application of a new family of phosphine-phosphites PC n OP(S)-H x (n = 1-4, x = 0 or 8) (Fig.…”

Section: Introductionsupporting

confidence: 71%

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Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

et al. 2012

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A series of new phosphine-phosphite ligands P(C)(n)OP (n = 1-4) have been synthesized and used for rhodium-catalyzed asymmetric hydrogenation of prochiral olefins in order to study the effect of the chelate ring size. Excellent ees (up to 97.5%) were obtained in the hydrogenation of dimethyl itaconate and an increase of activity and enantioselectivity was observed in the hydrogenation of (Z)-α-acetamidocinnamic acid methyl ester with the increasing length of the backbone of the ligands.

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Section: Introductionsupporting

confidence: 71%

“…Solvents were purified, dried and deoxygenated by standard methods. 21 hydroxymethyl-, 8 hydroxyethyl-, 9 hydroxypropyl-, 9 and hydroxybutyl-diphenylphosphine 10 were prepared according to the literature methods. 31 P{ 1 H}-, 1 H-and 13…”

Section: Experimental General Experimental Detailsmentioning

confidence: 99%

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

et al. 2012

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“…The complex [Rh(DPPB)Cl(solv)] has previously been used as a catalyst for the hydrogenation of ACA in organic solvents. 17 The hydrogenation rate is comparable to those rates observed for the [Rh(DPPBTS)(NBD)] ϩ catalysed hydrogenations of AAA at a pH higher than the pK a for the substrate. The reason for the extremely high rates observed at low pH is, however, hard to rationalise and must thus be further investigated.…”

Section: Rate Law and Mechanismsupporting

confidence: 59%

pH Effects on reaction rates in rhodium catalysed hydrogenation in water

Malmström¹,

Wendt²,

Andersson³

1999

J. Chem. Soc., Dalton Trans.

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“…It is well-known that the catalytic activity of the cationic [Rh(PPh 2 (CH 2 ) n PPh 2 ) 2 ] + (n ) 1-6) complexes is dependent on the size of the chelating ring. 23,[48][49][50] These complexes possess different solid-state structures, 21,22,51 solution behavior, 21,22,52 and chemical reactivity, 20,22,52-54 as n is varied from 1 to 6. The reaction of these complexes with CO and with H 2 illustrates major reactivity differences.…”

Section: Dynamic Behavior Of [Rh(dppb) 2 ]mentioning

confidence: 99%

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution

et al. 1996

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Treatment of an orange solution of [Rh(COD)(DPPB)] + BF 4 -(2) in MeOH with 2 equiv of NaBPh 4 at room temperature (RT) afforded an orange precipitate, [Rh(COD)(DPPB)] + BPh 4 -(3), in 94% yield. Reaction of the cationic rhodium complex 3 with H 2 under ambient conditions in CH 2 Cl 2 for 1 h gave the zwitterionic complex (η 6 -PhBPh 3 ) -Rh + (DPPB) (4) in quantitative yield. Although 3 is stable in the solid state, it has the propensity in solution to convert to the zwitterionic complexes (η 6 -PhBPh 3 ) -Rh + (COD) (1) and (η 6 -PhBPh 3 ) -Rh + -(DPPB) (4) along with a small amount of [Rh x (DPPB) 2x ] x+ [BPh 4 -] x . Addition of 1, 2, and 4 equiv of DPPB to the CD 2 Cl 2 solution of (η 6 -PhBPh 3 ) -Rh + (NBD) (6) under N 2 resulted in the formation of [Rh(NBD)(DPPB)] + BPh 4 -(7) and [Rh(DPPB) 2 ] + BPh 4 -(5) in ratios of 90/ 10, 57/43, and 0/100, respectively, while addition of 2 equiv of DPPB to the CD 2 Cl 2 solution of 6, under an atmosphere of H 2 at RT, gave 4 and 5 in an ratio of 35/65. "Slowed" η 6 -PhBPh 3 -rotation about the (η 6 -PhBPh 3 ) --Rh bond axis in (η 6 -PhBPh 3 ) -Rh + (DPPB) (4) was established by a variable-temperature 31 P{ 1 H} NMR study. Variable-temperature 31 P{ 1 H} NMR spectra of [Rh(DPPB) 2 ] + BPh 4 -(5) along with the low-temperature 31 P{ 1 H} COSY and EXSY NMR spectra demonstrated the presence of an equilibrium between [Rh(DPPB) 2 ] + (5R) and [Rh(DPPB)(µ-DPPB)] 2 2 + (5 ).

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Hydrogenation catalytique homogene a l'aide de complexes rhodium—diphosphines

Cited by 42 publications

References 9 publications

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

pH Effects on reaction rates in rhodium catalysed hydrogenation in water

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution

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Hydrogenation catalytique homogene a l'aide de complexes rhodium—diphosphines

Cited by 42 publications

References 9 publications

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

Phosphine–phosphite ligands: chelate ring size vs. activity and enantioselectivity relationships in asymmetric hydrogenation

pH Effects on reaction rates in rhodium catalysed hydrogenation in water

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic31P{1H} NMR Studies of (η6-PhBPh3)-Rh+(DPPB) and [Rh(DPPB)2]+BPh4-in Solution

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Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution