73365-03-4Relevant articles and documents
Supported Cobalt Nanoparticles for Hydroformylation Reactions
Hertrich, Maximilian Franz,Scharnagl, Florian Korbinian,Pews-Davtyan, Anahit,Kreyenschulte, Carsten Robert,Lund, Henrik,Bartling, Stephan,Jackstell, Ralf,Beller, Matthias
supporting information, p. 5534 - 5538 (2019/03/26)
Hydroformylation of olefins has been studied in the presence of specific heterogeneous cobalt nanoparticles. The catalytic materials were prepared by pyrolysis of preformed cobalt complexes deposited onto different inorganic supports. Atomic absorption spectroscopy (AAS) measurements indicated a correlation of catalyst activity and cobalt leaching as well as a strong influence of the heterogeneous support on the productivity. These new, low-cost, easy-to-handle catalysts can substitute more toxic, unstable and volatile cobalt carbonyl complexes for hydroformylations on a laboratory scale.
Effector enhanced enantioselective hydroformylation
Bai, Shao-Tao,Kluwer, Alexander M.,Reek, Joost N. H.
supporting information, p. 14151 - 14154 (2019/12/02)
In this communication, we report rhodium DIMPhos complexes with an integrated DIM-receptor that can bind carboxylate containing effectors and their application in the rhodium catalyzed hydroformylation reaction. The binding of chiral effectors in non-chiral [Rh(DIMPhos)] catalysts does not lead to enantioselective hydroformylation, but the binding of either achiral or chiral effectors can significantly enhance the enantioselectivity induced by the chiral Rh-metal complexes. For example, the supramolecular complex [Rh]/[1S?L3] displays high regio- and enantioselectivity in the hydroformylation of vinyl acetate (72% ee, and b/l >99), whereas in absence of this effector the ee is around 17%.
KetoABNO/NOx Cocatalytic Aerobic Oxidation of Aldehydes to Carboxylic Acids and Access to α-Chiral Carboxylic Acids via Sequential Asymmetric Hydroformylation/Oxidation
Miles, Kelsey C.,Abrams, M. Leigh,Landis, Clark R.,Stahl, Shannon S.
supporting information, p. 3590 - 3593 (2016/08/16)
A method for aerobic oxidation of aldehydes to carboxylic acids has been developed using organic nitroxyl and NOx cocatalysts. KetoABNO (9-azabicyclo[3.3.1]nonan-3-one N-oxyl) and NaNO2 were identified as the optimal nitroxyl and NOx sources, respectively. The mildness of the reaction conditions enables sequential asymmetric hydroformylation of alkenes/aerobic aldehyde oxidation to access α-chiral carboxylic acids without racemization. The scope, utility, and limitations of the oxidation method are further evaluated with a series of achiral aldehydes bearing diverse functional groups.
Rhodium catalyzed hydroformylation with formaldehyde and an external H 2-source
Uhlemann, Marcus,Doerfelt, Stephan,B?rner, Armin
, p. 2209 - 2211 (2013/05/09)
The efficiency of the syngas-free rhodium catalyzed hydroformylation of olefins with formaldehyde can be significantly improved by the addition of hydrogen gas or formic acid.
New tetraphosphorus ligands for highly linear selective hydroformylation of allyl and vinyl derivatives
Cai, Chaoxian,Yu, Shichao,Cao, Bonan,Zhang, Xumu
experimental part, p. 9992 - 9998 (2012/09/07)
New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of functionalized allyl and vinyl derivatives. Remarkably high linear selectivity was obtained by these tetraphosphorus ligands. The ligand that bears strong electron-withdrawing 2,4-difluorophenyl groups is the most effective one in affording linear aldehydes. The Rh/tetraphosphorus ligand catalyst is highly effective to produce linear aldehydes from functionalized allyl derivatives with heteroatoms or aromatic groups directly adjacent to the allyl group. For vinyl derivatives, the ligand is highly linear selective for acrylic derivatives, styrene, vinyl pyridine, and vinyl phthalimide. Linear to branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. New tetraphosphorus ligands have been developed and applied in the rhodium-catalyzed regioselective hydroformylation of a variety of allyl and vinyl olefins (see scheme). Remarkably high linear selectivities were obtained by these ligands. Linear-to-branch ratios of 26:1 and 10:1 were obtained for the hydroformylation of styrene and allyl cyanide, respectively. Copyright
Synthesis of novel rhodium phosphite catalysts for efficient and selective isomerization-hydroformylation reactions
Piras, Irene,Jennerjahn, Reiko,Jackstell, Ralf,Baumann, Wolfgang,Spannenberg, Anke,Franke, Robert,Wiese, Klaus-Diether,Beller, Matthias
experimental part, p. 479 - 486 (2010/04/05)
New modular H8-BINOL-based phosphite ligands have been synthesized. High activity and regioselectivity has been achieved in the rhodium-catalyzed isomerization-hydroformylation of internal olefins. The active catalysts have been characterized by in situ NMR studies.
Highly regioselective hydroformylation of enamides with phosphite ligands
Saidi, Ourida,Ruan, Jiwu,Vinci, Daniele,Wu, Xiaofeng,Xiao, Jianliang
, p. 3516 - 3519 (2008/09/21)
The regioselective hydroformylation of enamides with a catalyst derived from monodentate phosphites and Rh(acac)(CO)2 was studied. In the hydroformylation of N-vinylphthalimide, all the biphenol-based ligands led to the branched aldehyde; the fastest reaction was observed when using a sterically bulky phosphite. The olefins (E)-N-propenylphthalimide, vinylpyrrolidone, vinylcaprolactam and vinylcarbazole were also investigated.
Highly enantioselective hydroformylation of olefins catalyzed by rhodium(I) complexes of new chiral phosphine-phosphite ligands
Nozaki, Kyoko,Sakai, Nozomu,Nanno, Tetsuo,Higashijima, Takanori,Mano, Satoshi,Horiuchi, Toshihide,Takaya, Hidemasa
, p. 4413 - 4423 (2007/10/03)
A new chiral phosphine-phosphite ligand, (R)-2-(diphenylphosphino)- 1,1'-binaphthalen-2'-yl (S)-1,1'-binaphthalene-2,2'-diyl phosphite [(R,S)- BINAPHOS, (R,S)-2a], was synthesized. Its Rh(I) complex was prepared, and its structure has been characterized by 1H and 31P NMR spectroscopy. Using Rh(I) complexes of (R,S)-2a and its enantiomer, highly enantioselective hydroformylation of styrene has been performed (94% ee, iso/normal = 88/12). The catalyst system was also effective for a variety of other olefins. Some other phosphine-phosphite ligands bearing 1,1'-binaphthyl and biphenyl backbones, such as (S)-3,3'-dichloro-6-(diphenylphosphino)-2,2',4,4'- tetramethylbiphenyl-6'-yl (R)-1,1'-binaphthalene-2,2'-diyl phosphite [(S,R)- BIPHEMPHOS. (S,R)-5a], (R,R)-2a, (R,S)-2b, (R)-2c, and (R)-5b, were tested for asymmetric hydroformylation. The results indicate that the sense of enantioface selection for the prochiral olefins is mainly determined by the absolute configuration of the phosphine site, for example, the (R)-2- (diphenylphosphino)-1,1'-binaphthalen-2'-yl group in (R,S)-2a. The relative configurations of the two biaryl groups in the phosphine-phosphites play crucial roles in the degree of the enantioselectivities, that is, the (R,S)- isomer generally gives products in high ee's and the (R*,R*)-isomer does in low ee's. Treatment of Rh(acac)[(R,S)-2a] with a 1:1 mixture of carbon monoxide and hydrogen gave a hydridorhodium complex. RhH-(CO)2[(R,S)-2a], as a single species. Trigonal bipyramidal structure is suggested for this complex, in which the hydride and the phosphite moiety are located at the apical positions and the phosphine and the two carbonyls occupy the equatorial positions. The interchange of the phosphine and the phosphite sites with each other through rapid pseudorotations has not been observed in RhH(CO)2[(R,S)-2a]. The structural deviations of the monohydride complexes from an ideal trigonal bipyramid seem to be larger in (R*,R*)-isomers than in the corresponding (R*,S*)-isomers. The existence of only one active species involved in the Rh(1)-(R,S)-2a-catalyzed hydroformylation has been manifested by the plot of ln([R]/[S]) of the hydroformylation product vs the reciprocals of the reaction temperatures. The higher thermodynamic stability of Rh(acac)[(R,S)-2a] than its diastereomer Rh(acac)[(R,R)-2a] is demonstrated in relation to the restricted configuration of (R)-2c to (R,S)- 2c in its complex formation with Rh(1).
ENZYME CATALYSED TRANSESTERIFICATION OF AMINOPHOSPHONIC ACIDS. II-ISOTHREONINE-P ANALOGUES
Heisler, A.,Rabiller, C.,Haegele, G.
, p. 273 - 280 (2007/10/02)
In this work, we used lipases to resolve kinetically the four possible configurations of an important aminophosphonic acid: isothreonine-P (isoTHR-P).We synthesized a diastereomeric mixture of N-Cbz-isoTHR-P(O)(OEt)2 and also each diastereomer of isoTHR-P(O)(OEt)2.Several enzymatic reactions were then performed (hydrolysis and transesterification) with these compounds.The lipases used (mainly Pseudomonas fluorescens and Candida rugosa) proved to be diastereoselective and chemioselective, but no enantioselectivity was observed.Key words: Aminophosphonic acids, isothreonine-P, lipases, kinetic resolution.
Acyclic stereoselection in the tertiary amine-catalysed addition of activated vinyl systems (Baylis-Hillman reaction) to protected chiral α-hydroxy and α-amino aldehydes
Manickum, Thavrin,Ross, Gregory H. P.
, p. 1 - 16 (2007/10/03)
The non chelation-controlled aldol-type addition of the ambident vinyl α anions derived from acrylic esters and methyl vinyl ketone to a series of protected chiral α-hydroxy and α-amino aldehydes has been investigated in order to assess some of the factors which contribute to the control of the diastereofacial selectivity.Whlist the α-methylene-β,γ-disubstituted carbonyl products showed a general preference for selectivity, some examples of syn predominance were made possible via a 'substituent tuning'approach.The observed diastereomer ratios have been interpreted in terms of the Felkin model and the Anh-Eisenstein proposals for 1,2-asymmetric induction.Simple steric effects appear to be as important as ?-orbital energies in the designation of the large 'anti group' for the application of these transition-state interpretations.Attempts to improve the overall induction via double diastereoselection approach, which combines the 1,5-induction of chiral acrylates with the 1,2-induction already present, were largely inconclusive.Methods for the routine NMR assignment of the relevant stereo-substructures have been assessed and the use of novel complementary technique is described.
