14367-67-0Relevant academic research and scientific papers
Highly efficient asymmetric hydrogenation of α,β-unsaturated carboxylic acids catalyzed by ruthenium(II)-dipyridylphosphine complexes
Qiu, Liqin,Li, Yue-Ming,Kwong, Fuk Yee,Yu, Wing-Yiu,Fan, Qing-Hua,Chan, Albert S. C.
, p. 517 - 520 (2007)
Two types of catalysts [RuL(benzene)Cl]Cl and Ru(OCOCH3) 2L with the dipyridylphosphine ligands P-Phos and Xyl-P-Phos were applied in the asymmetric hydrogenation of α,β-unsaturated carboxylic acids. The cationic complexes [RuL(benzene)Cl]Cl were found to be superior to the corresponding neutral complex Ru(OCOCH3)2L in this type of reactions. The catalysts exhibited excellent activities and enantioselectivities (up to 97% ee) in the asymmetric hydrogenation.
L-Valinol and L-phenylalaninol-derived 2-phenylamino-2-oxazolines as chiral auxiliaries in asymmetric alkylations
Lee, Gue-Jae,Kim, Taek Hyeon,Kim, Jae Nyoung,Lee, Uk
, p. 9 - 12 (2002)
Lithium enolates of N-acyl phenyliminooxazolidine auxiliaries reacted with alkyl halides to produce the α-alkylated products with very high diastereofacial selectivity (up to >99% d.e.). The products were readily cleaved by simple alkaline hydrolysis to give homochiral carboxylic acids and could also be directly converted to aldehydes and other acid derivatives such as esters and amides.
Enantioselective Synthesis of Chiral Carboxylic Acids from Alkynes and Formic Acid by Nickel-Catalyzed Cascade Reactions: Facile Synthesis of Profens
Fu, Kaiyue,Ma, Yu,Sun, Yaxin,Tang, Bo,Yang, Guang,Yang, Peng,Yue, Jieyu,Zhang, Li,Zhou, Jianrong Steve
supporting information, (2021/11/22)
We report a stereoselective conversion of terminal alkynes to α-chiral carboxylic acids using a nickel-catalyzed domino hydrocarboxylation-transfer hydrogenation reaction. A simple nickel/BenzP* catalyst displayed high activity in both steps of regioselective hydrocarboxylation of alkynes and subsequent asymmetric transfer hydrogenation. The reaction was successfully applied in enantioselective preparation of three nonsteroidal anti-inflammatory profens (>90 % ees) and the chiral fragment of AZD2716.
Model Studies on the Enzyme-Regulated Stereodivergent Cascade Passerini Reaction
Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard,Samsonowicz-Górski, Jan,Wilk, Monika
supporting information, p. 4161 - 4165 (2021/08/24)
The synthesis of chiral α-acyloxy carboxamides containing two stereogenic centers continues to be a challenging field of organic chemistry. Herein, we have proposed and proved the feasibility of an enzyme regulated-cascade reaction, which using the same substrates enables the formation of individual stereoisomers of α-acyloxy carboxamides with up to 99 % ee. The access to the individual stereoisomeric products has been achieved by a combination of the enzymatic kinetic resolution of racemic vinyl esters, subsequent Passerini reaction, and enzymatic kinetic resolution of formed α-acyloxy carboxamides. The presented studies are promising in exploratory proof-of-concept of enzyme-controlled stereodivergent cascade to form an important class of chiral compounds for medicinal chemistry.
Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H2 Cleavage
Chirik, Paul J.,Shevlin, Michael,Zhong, Hongyu
supporting information, (2020/03/13)
The asymmetric hydrogenation of α,β-unsaturated carboxylic acids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri-, and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylic acids including Naproxen, (S)-Flurbiprofen, and a d-DOPA precursor. Turnover numbers of up to 200 were routinely obtained. Compatibility with common organic functional groups was observed with the reduced cobalt(0) precatalysts, and protic solvents such as methanol and isopropanol were identified as optimal. A series of bis(phosphine) cobalt(II) bis(pivalate) complexes, which bear structural similarity to state-of-the-art ruthenium(II) catalysts, were synthesized, characterized, and proved catalytically competent. X-band EPR experiments revealed bis(phosphine)cobalt(II) bis(carboxylate)s were generated in catalytic reactions and were identified as catalyst resting states. Isolation and characterization of a cobalt(II)-substrate complex from a stoichiometric reaction suggests that alkene insertion into the cobalt hydride occurred in the presence of free carboxylic acid, producing the same alkane enantiomer as that from the catalytic reaction. Deuterium labeling studies established homolytic H2 (or D2) activation by Co(0) and cis addition of H2 (or D2) across alkene double bonds, reminiscent of rhodium(I) catalysts but distinct from ruthenium(II) and nickel(II) carboxylates that operate by heterolytic H2 cleavage pathways.
Electrocatalytic asymmetric hydrogenation of α,β-unsaturated acids in a PEM reactor with cinchona-modified palladium catalysts
Atobe, Mahito,Fukazawa, Atsushi,Hashimoto, Yasushi,Sato, Yasushi,Tanaka, Kenta
, (2020/04/28)
We have developed an electrocatalytic asymmetric hydrogenation reaction using a proton-exchange membrane (PEM) reactor that employs a polymer electrolyte fuel cell and industrial electrolysis technologies. Reasonable enantioselectivities and excellent current efficiencies were obtained in the asymmetric hydrogenation of α-phenylcinnamic acid under mild conditions without adding a supporting electrolyte. The current density was crucial to achieving the improved results observed.
Enantioselective Enzymatic Reduction of Acrylic Acids
An, Chihui,Shaw, Megan H.,Tharp, Annika,Verma, Deeptak,Li, Hongming,Wang, Heather,Wang, Xiao
supporting information, p. 8320 - 8325 (2020/11/03)
An ene-reductase (ERED 36) with broad substrate specificity was identified, and optimization studies led to the development of an enzymatic protocol for the reduction of α,β-unsaturated acids under mild, aqueous conditions. The substrate scope includes aromatic- A nd aliphatic-substituted acrylic acids, as well as cyclic α,β-substituted acrylic acids, yielding chiral α-substituted acids with exquisite levels of enantioselectivity (>99% ee).
Controllable Intramolecular Unactivated C(sp3)-H Amination and Oxygenation of Carbamates
Guo, Qihang,Ren, Xiang,Lu, Zhan
supporting information, p. 880 - 884 (2019/05/16)
Dual catalyst-controlled intramolecular unactivated C(sp3)-H amination and oxygenation of carbamates merging visible-light photocatalysis and earth-abundant transition metal catalysis have been reported. Useful amino alcohol and diol derivatives could be selectively obtained from readily available tertiary alcohol derivatives. The possible mechanisms have been proposed via a 1,5-HAT process followed by Lewis acid-controlled cyclization. The nickel and zinc catalysts inhibit the formation of oxygenation and amination products, respectively. An interesting phenomenon of chirality transfer is also observed.
Deracemizing α-Branched Carboxylic Acids by Catalytic Asymmetric Protonation of Bis-Silyl Ketene Acetals with Water or Methanol
Mandrelli, Francesca,Blond, Aurélie,James, Thomas,Kim, Hyejin,List, Benjamin
, p. 11479 - 11482 (2019/07/18)
We report a highly enantioselective catalytic protonation of bis-silyl ketene acetals. Our method delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.
Direct Lewis Acid Catalyzed Conversion of Enantioenriched N-Acyloxazolidinones to Chiral Esters, Amides, and Acids
Stevens, Jason M.,Parra-Rivera, Ana Cristina,Dixon, Darryl D.,Beutner, Gregory L.,Delmonte, Albert J.,Frantz, Doug E.,Janey, Jacob M.,Paulson, James,Talley, Michael R.
, p. 14245 - 14261 (2019/01/03)
The identification of Yb(OTf)3 through a multivariable high-throughput experimentation strategy has enabled a unified protocol for the direct conversion of enantioenriched N-acyloxazolidinones to the corresponding chiral esters, amides, and carboxylic acids. This straightforward and catalytic method has shown remarkable chemoselectivity for substitution at the acyclic N-acyl carbonyl for a diverse array of N-acyloxazolidinone substrates. The ionic radius of the Lewis acid catalyst was demonstrated as a key driver of catalyst performance that led to the identification of a robust and scalable esterification of a pharmaceutical intermediate using catalytic Y(OTf)3.
