Chiral phosphite-phosphoroamidites: A new class of ligand for asymmetric catalytic hydrogenation

Dieguez,Ruiz,Claver

, p. 2702 - 2703 (2001)

A series of novel phosphite-phosphoroamidite ligands, derived from readily available D-xylose, has been used for the first time in the asymmetric Rh-catalyzed hydrogenation of a series of α,β-unsaturated carboxylic acid derivatives with excellent enantios

Kinetic resolution of N-acetyl-DL-alanine methyl ester using immobilized Escherichia coli cells bearing recombinant esterase from Bacillus cereus

Zheng, Jianyong,Lan, Xing,Huang, Lijuan,Zhang, Yinjun,Wang, Zhao

, p. 907 - 912 (2018)

D-alanine is widely used in medicine, food, additives, cosmetics, and other consumer items. Esterase derived from Bacillus cereus WZZ001 exhibits high hydrolytic activity and stereoselectivity. In this study, we expressed the esterase gene in Escherichia coli BL21 (DE3). We analyzed the biocatalytic resolution of N-acetyl-DL-alanine methyl ester by immobilized whole E.?coli BL21 (DE3) cells, which were prepared through embedding and cross-linking. We analyzed biocatalytic resolution under the optimal conditions of pH of 7.0, temperature of 40°C and substrate concentration of at 700?mM with an enantiomeric excess of 99.99% and e.e.p of 99.50%. The immobilized recombinant B.?cereus esterase E.?coli BL21 (DE3) cells exhibited excellent reusability and retained 86.04% of their initial activity after 15 cycles of repeated reactions. The immobilized cells are efficient and stable biocatalysts for the preparation of N-acetyl-D-alanine methyl esters.

Directed evolution of enantioselective hybrid catalysts: a novel concept in asymmetric catalysis

Reetz, Manfred T.,Rentzsch, Martin,Pletsch, Andreas,Maywald, Matthias,Maiwald, Peter,Peyralans, Jér?me J.-P.,Maichele, Andrea,Fu, Yu,Jiao, Ning,Hollmann, Frank,Mondière, Régis,Taglieber, Andreas

, p. 6404 - 6414 (2007)

The concept of directed evolution of enantioselective hybrid catalysts was proposed in 2001/2002 and implemented experimentally for the first time in a proof-of-concept study in 2006. The idea is based on directed evolution, which comprises repeating cycl

Synthesis and application of C2-symmetric diamino FERRIPHOS as ligands for enantioselective Rh-catalyzed preparation of chiral α-amino acids

Almena Perea, Juan J.,Lotz, Matthias,Knochel, Paul

, p. 375 - 384 (1999)

C2-Symmetrical ferrocenyl diamino diphosphines (diamino FERRIPHOS ligands) proved to be excellent ligands for the rhodium-catalyzed enantioselective reduction of methyl α-acetamidoacrylates. The straightforward synthesis, their air stability an

Chiral phosphine-phosphite ligands in the highly enantioselective rhodium-catalyzed asymmetric hydrogenation

Deerenberg,Pamies,Dieguez,Claver,Kamer,Van Leeuwen

, p. 7626 - 7631 (2001)

We have investigated a series of enantiopure phosphine-phosphite ligands (P1-P2 = ligands 1-4) in the rhodium-catalyzed asymmetric hydrogenation reaction. Intermediate [Rh(P1-P2)(cod)]BF4 and [Rh(Psu

Highly Enantioselective Hydrogenation of α-Dehydroamino Acids by Rhodium Complexes with New Unsymmetric P-Chirogenic Bisphosphine Ligands

Ohashi, Atsushi,Imamoto, Tsuneo

, p. 373 - 375 (2001)

(Matrix Presented) New rhodium catalysts with unsymmetric P-chirogenic bis(phosphino)ethanes, BisP*-Rh, exhibited very high enantioselectivity (98-99%) in the hydrogenation of α-dehydroamino acid derivatives. Such high enantioselectivity should result fro

Versatile synthesis of chiral aminophosphine phosphinites (AMPPs) as ligands for enantioselective hydrogenation

Dubrovina, Natalia V.,Tararov, Vitali I.,Kadyrova, Zenfira,Monsees, Axel,Boerner, Armin

, p. 2047 - 2051 (2004)

New chiral aminophosphine phosphinite (AMPP) ligands with different P-aryl substituents were prepared from (1R,3S,4S)-2-azabicyclo[2.2.1]hept-3-ylmethanol by a new and chemoselective synthetic approach. The ligands showed good enantioselectivity (up to 91

Rh-catalysed asymmetric hydrogenations with a dynamic library of chiral tropos phosphorus-ligands

Monti, Chiara,Gennari, Cesare,Piarulli, Umberto

, p. 6859 - 6862 (2004)

A number of homo- (16) and heterocombinations (115) of chiral tropos phosphorus-ligands were screened for the rhodium catalysed asymmetric hydrogenation of methyl N-acetamido acrylate, resulting in the identification of an extremely effective and enantioselective (100% yield, 94% ee) phosphite/phosphoramidite heterocombination. A library of 16 chiral tropos phosphorus-ligands, based on a chiral P-bound alcohol or secondary amine and a flexible (tropos) P-bound biphenol unit, was synthesised. This ligand library allowed the screening of 16 homocombinations and 115 heterocombinations for the rhodium catalysed asymmetric hydrogenation of methyl N-acetamido acrylate. The screening resulted in the identification of a phosphite/phosphoramidite heterocombination, which proved to be extremely effective and enantioselective (100% yield, 94% ee).

New rhodacarborane-phosphoramidite catalyst system for enantioselective hydrogenation of functionalized olefins and molecular structure of the chiral catalyst precursor [3,3-{(S)-PipPhos}2-3-H-1,2-(o -xylylene)- closo -3,1,2-RhC2B

Alekseev, Leonid S.,Lyubimov, Sergey E.,Dolgushin, Fedor M.,Novikov, Valentin V.,Davankov, Vadim A.,Chizhevsky, Igor T.

, p. 1942 - 1950 (2011)

Formally 16-electron closo- and pseudocloso-(a3-cyclooctenyl) rhodacarboranes of the general formula [3-{(1-3-η3)-C 8H13}-1,2-R,R-3,1,2-RhC2B9H 9] (1 (closo), R, R = μ-1′,2′-CHs

The parallel synthesis of peptide based phosphine ligands

Gilbertson, Scott R.,Wang, Xifang

, p. 11609 - 11618 (1999)

Chemistry is reported that allows for the synthesis and screening of phosphine ligands by standard combinatorial technology. To demonstrate the method, libraries of phosphine containing peptides were synthesized. Rhodium was complexed to the phosphine lig

The role of additional solvents in transition metal complex catalyzed asymmetric reductions in ionic liquid containing systems

Wolfson, Adi,Vankelecom, Ivo F.J.,Jacobs, Pierre A.

, p. 3558 - 3566 (2005)

When ionic liquids (ILs) are employed as solvents for transition metal complex (TMC) catalyzed reductions, a second solvent can be added to increase the efficiency of the catalytic cycle and the solubility of the reactant in the IL phase. Two industrially relevant asymmetric hydrogenations, the enantioselective reductions of methyl 2-acetamidoacrylate with Rh-EtDuPHOS and methyl acetoacetate with Ru-BINAP, were performed in different catalytic systems including 1-butyl-3-methylimidazolium hexafluorophosphate/ tetrafluoroborate as ILs. Product separation and TMC recycling was performed by extracting the product from the reaction mixture. This can be accomplished by cooling the system, by adding an excess of the second solvent or by adding a third solvent. A high solubility of the second solvent in the IL catalytic phase favors the reaction activity, but can induce leaching of the IL and TMC.

Mixtures of chiral and achiral monodentate ligands in asymmetric Rh-catalyzed olefin hydrogenation: Reversal of enantioselectivity

Reetz, Manfred T.,Mehler, Gerlinde

, p. 4593 - 4596 (2003)

The recently described method of combinatorial asymmetric transition metal catalysis based on the use of mixtures of chiral monodentate P-ligands has been extended to include mixtures of chiral and achiral monodentate P-ligands, reversal of enantioselectivity in Rh-catalyzed olefin hydrogenation being possible in appropriate cases.

Rationally designed improvement of the bis(phospholano)ethane ligand for asymmetric hydrogenation leads to a reappraisal of the factors governing the enantioselectivity of Duphos catalysts

Fernandez,Gillon,Heslop,Horwood,Hyett,Orpen,Pringle

, p. 1663 - 1664 (2000)

Enhancement of enantioselectivity in hydrogenations catalysed by δ vs. λ, rhodium chelate complexes of trans-1,2-bis(phospholano)cyclopentanes cannot be rationalised using the current quadrant model for Duphos ligands and therefore a new consistent model

Highly enantioselective Rh-catalyzed hydrogenation based on phosphine-phosphite ligands derived from carbohydrates

Pamies,Dieguez,Net,Ruiz,Claver

, p. 8364 - 8369 (2001)

A new class of efficient catalysts was developed for the asymmetric hydrogenation of α,β-unsaturated carboxylic acid derivatives by synthesizing a series of novel phosphine-phosphite ligands (4a-d) derived from readily available D-(+)-xylose. Excellent en

Mechanistically Guided One Pot Synthesis of Phosphine-Phosphite and Its Implication in Asymmetric Hydrogenation

Sen, Anirban,Kumar, Rohit,Pandey, Swechchha,Vipin Raj,Kumar, Pawan,Vanka, Kumar,Chikkali, Samir H.

supporting information, (2022/01/11)

Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an O-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72 %). When L1 was treated with [Rh], 31P NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92 %). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1–2 bar H2 pressure, at room temperature. The practical relevance of L1 is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.

Erratum: SPHENOL, a new chiral framework for asymmetric synthesis (Journal of the American Chemical Society (2021) 143:32 (12445-12449) DOI: 10.1021/jacs.1c05709)

Ge, Shulin,Sun, Jianwei,Zhang, Ronghua

supporting information, p. 17872 - 17872 (2021/11/24)

Page 12447. The description of the synthesis of 3,3'-diiodide 9 in the paragraph related to Scheme 4a is incorrect. The enantiopure compound 9 was obtained from SPHENOL with a methoxymethyl group as the protecting group, instead of a methyl group. The detailed procedures are provided in the updated Supporting Information. The third sentence of that paragraph, "A three-step sequence involving protection of the diol into methyl ether.", should be replaced by "A three-step sequence involving protection of the diol into methoxymethyl ether.". In footnote a of Scheme 4, "aReaction conditions: (i) NaH, MeI; (ii) nBuLi, TMEDA; I2; (iii) BBr3, DCM.", should be replaced by "aReaction conditions: (i) NaH, MOMBr; (ii) nBuLi, TMEDA, I2; (iii) HCl (6.0 M), 1,4-dioxane.".

P-chirogenic diphosphazanes with axially chiral substituents and their use in rh-catalyzed asymmetric hydrogenation

Moritz, Jan-Ole,Chakrabortty, Soumyadeep,Bernd H. Mu.ller,Spannenberg, Anke,Kamer, Paul C. J.

, p. 14537 - 14544 (2020/12/29)

A convenient synthesis of enantiopure P-chirogenic diphosphazanes incorporating bulky bisphenol and 1,1′-bi-2-naphtholderived substituents via the functionalization of a readily accessible enantiopure lithium phosphinoamide with chlorophosphoridites was developed. Since the product requires no subsequent deprotection, the protocol provides an easy, convenient synthesis of P-chirogenic ligands on the gram scale. The ligands were applied in the Rh-catalyzed asymmetric hydrogenation of benchmark substrates furnishing enantiomeric excess values up to 96%.