Asymmetric hydrogenation. Rhodium chiral bisphosphine catalyst

Vineyard, B. D.; Knowles, William S.; Sabacky, M. J.; Bachman, Gerald L.; Weinkauff, D. J.

doi:10.1021/ja00460a018

Cited by 826 publications

(333 citation statements)

References 1 publication

Supporting

Mentioning

323

Contrasting

Unclassified

Order By: Relevance

“…{/?o): the deshielding through coordination is again well denlonstrated, and there are now two sets of phenyl groups. These very likely approximate an edge-face conformation, a geometry that has been demonstrated recently in several Ph2PnPPh2 complexes, including IrCl(COD)(diop) (45) and Rh-(COD)(diphosphine)+ species (46)(47)(48), where COD = 1,s-cyclooctadiene and diphosphine = 1,2-bis-[(anisole)(phenjrlphosphino)]ethane and 2,3-bis(diphenylphosphino)buta~le. The orientatio~l of the phenyl groups appears critical for the high efficiency of such complexes as catalysts for asymmetric hydrogenation of prochiral olefinic substrates (1 3, 46, 48).…”

Section: Resultssupporting

confidence: 56%

Bis(ditertiaryphosphine) complexes of rhodium(I). Synthesis, spectroscopy, and activity for catalytic hydrogenation

James¹,

Mahajan²

1979

Can. J. Chem.

View full text Add to dashboard Cite

Rhodium(1)-bis(ditertiaryphosphine) complexes of the general formula R~( P^P ) , ~1(PnP = Ph,P(CH,),,PPh,, n = 1-4, and (+)-diop (diop = 2,3-0-isopropylidene 2,3-dihydroxy-1,4-bis(dipheny1phosphino)butane) have been prepared by treating [Rh(cyclooctene),CI], with the appropriate ditertiaryphosphine. The n = 1 and n = 4 and diop species are five-coordinate in the solid state and in non-polar solvents, while the n = 2 and 3 species contain ionic chloride. The cationic complexes R~( P P ) , + x -were prepared from the R~(P^P),CI species by adding AgX (X = SbF,, PF,, BF,). Reaction of the chloro coniplexes with borohydride has yielded the hydrides, HRh(PnP),, for the n = 2 and 3 diphosphines, and for (+)-diop. 'H and 31P nmr, as well as visible rpectral data, are presented: a solventdependent deshielding of ort/~o protons of the phenyl groups is observed in some of the cornplexes, and the ligand CH2 protons are coupled to the rhodium in the Rh(Ph,PCH,PPh2),+ cation; the P atom in this bis(dipheny1phosphino) ligand shows an usual high field shift on coordination to rhodium.Preliminary kinetic data for catalytic hydrogenation of methylenesuccinic acid show that the cationic and hydrido colnplexes are more active than the corresponding chloro coniplexes, and that activity generally increases with increasing chain length of the diphosphine. avec la phosphineditertiaire appropriee. Les especes ou n = 1, IZ = 4 et diop sont pentacoordonnees a I'ttat solide et dans des solvants non-polaires alors que les especes ou 11 = 2 et 12 = 3 contiennent du chlorure ionique. On a prepare les complexes cationiques R~(P-P),+x-a partir des especes Rh(PAP),C1 auxquelles on a ajoute du AgX (X = SbF,, PF,, BF,). La reaction des complexes chlores avec le borohydrure conduit aux hydrures, HR~(P-P),, pour les diphosphines ou tr = 2 et 3 et pour le (+)-diop. On presente les spectres rnin 'H et 3'P de meme que les spectres dans le visible: dans quelques-un des complexes, on observe un deblindage des protons ortho des groupes phenyles qui depend du solvent et, dans le cation Rh(Ph,PCH,PPh,),-, les protons du CH, du ligand sont couples au rhodium: l'aton~e de P de ce ligand bis(dipheny1phosphino) subit un deplacement usuel vers les hauts champs par coordination avec le rhodium.Des donnees cinetiques preliminaires concernant Ishydrogenation catalytique de I'acide methylenesuccinique montrent que les con~plexes cationiques et hybrido sont plus actifs que Ics complexes chloro correspondants et que gentralement I'activiti augmente avec une augmentation de la longueur de la chaine de la diphosphine.[Traduit par le journal]

show abstract

Section: Resultssupporting

confidence: 56%

Bis(ditertiaryphosphine) complexes of rhodium(I). Synthesis, spectroscopy, and activity for catalytic hydrogenation

James¹,

Mahajan²

1979

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…The asymmetric synthesis has gained importance since 2001 when it was awarded the Nobel Prize in Chemistry to Knowles, Noyori and Sharples by scientific contributions in the field of asymmetric homogeneous catalysis 1 . Since then, and due to a growing demand for enantiomerically pure products for industry, there has been an attempt to homogeneous asymmetric hydrogenation of substrates for the production of chiral products as herbicides, insecticides, food, fragrances and especially drugs 2,3 .…”

Section: Introductionmentioning

confidence: 99%

Silica Supported Rhodium Metal Nanoparticles Stabilized With (-)-Diop. Effect of Ligand Concentration and Metal Loading on the Enantioselective Hydrogenation of Ketones

Ruiz¹,

Mella²,

Fierro

et al. 2012

J. Chil. Chem. Soc.

View full text Add to dashboard Cite

Supported nanoparticles (NPs) in presence of chiral ligand (L) were synthesized for their use in enantioselective hydrogenation reactions. Catalysts were obtained by chemical reduction from rhodium chloride hydrate, RhCl 3 ×3H 2 O, in presence of (-)-DIOP ligand ((4R,5R)-4,5-Bis(diphenylphosphino-methyl)-2,2-dimethyl-1,3-dioxolane) that allows to control NPs growing and to obtain solids having chiral surfaces. Chirally stabilized rhodium NPs on SiO 2 were characterized using techniques such as: TEM, electron diffraction, EDS, nitrogen adsorption-desorption isotherms and XPS.This work includes the study of some variables such as metal loading and ligand concentration and their effect in metal core sizes, catalytic activity and enantioselectivity. Catalysts properties have also been evaluated in the hydrogenation of substrates: acetophenone (AP), 1-phenyl-1,2-propanedione (PPD), 3,4-hexanedione (HD), 2,3-butanedione (BD) and ethyl pyruvate (EP) as reaction test.Ligand plays a fundamental role in the synthesis of NPs and enantioselectivity in hydrogenations reactions. That is, due to it generates metal particle size < 5.8 nm compared with unstabilized systems that generate average diameter around 14 nm. Results indicate increased activity in catalytic systems obtained from the stabilization of NPs. Enantioselectivity levels reach values up to 53% due to the chiral ligand is on the catalysts surface.

show abstract

“…Consequently, the two kinds of quadrant of the chiral template (first and third vs. second and fourth) are clearly differentiated spatially, where the second and fourth quadrants are sterically congested, while the first and third ones are relatively uncrowded. (R,R)-CHIRAPHOS 23 and (R,R)-DIPAMP 24 form a similar chiral environment with metals.…”

mentioning

confidence: 98%