10606-72-1Relevant academic research and scientific papers
Enantioselective catalytic synthesis of ethyl mandelate derivatives using Rh(I)-NHC catalysts and organoboron reagents
Marques, Carolina S.,Burke, Anthony J.
, p. 628 - 632 (2013)
Herein we describe for the first time the enantioselective catalytic arylation of ethyl glyoxalate using phenylboron reagents and chiral rhodium(I)-NHC catalysts. KOtBu was the base of choice, along with tert-amyl alcohol as the solvent. A novel chiral bis-imidazolium salt was synthesized and evaluated for the first time in this catalytic transformation. Although moderate enantioselectivities (up to 34% ee) were obtained for the phenylation reaction, despite the excellent yields, very low enantioselectivities were obtained using other arylboronic acids with a variety of chiral rhodium(I)-NHC catalysts.
Chiral organometallic NADH mimics: Highly stereoselective reductions of ethyl benzoylformate with a 1,4-dihydronicotinoyl fragment attached to the homochiral auxiliary 5-C5H5)Fe(CO)(PPh3)> and possessing a homochiral β-hydroxy-carboxamide at C-5.
Burgess, Vicky A.,Davies, Stephen G.,Skerlj, Renato T.,Whittaker, Mark
, p. 871 - 901 (1992)
A series of homochiral organometallic NADH mimics incorporating the chiral auxiliary 5-C5H5)Fe(CO)(PPh3)> at the C-3 carbonyl and a chiral carboxamide at C-5 of a 1,4-dihydronicotinoyl fragment have been prepared.These complexes were shown to stereoselectively reduce ethyl benzoylformate to either (R)- or (S)-ethyl mandelate by a combination of steric and chelation control.For example, complex (R,R)-12 bearing a carboxamide derived from (R)-(+)-methylbenzylamine afforded (R)-ethyl mandelate in 89percent enantiomeric excess.Utilisation of complexes (R,S)-19a and (R,R,S)-22a bearing chiral β-hydroxy-carboxamides derived from valinol and norephedrine respectively gave the (R)-ethyl mandelate in greater than 97percent enantiomeric excess.
Chiral-at-Iron Catalyst: Expanding the Chemical Space for Asymmetric Earth-Abundant Metal Catalysis
Hong, Yubiao,Jarrige, Lucie,Harms, Klaus,Meggers, Eric
, p. 4569 - 4572 (2019)
A new class of chiral iron catalysts is introduced that contains exclusively achiral ligands with the overall chirality being the result of a stereogenic iron center. Specifically, iron(II) is cis-coordinated to two N-(2-pyridyl)-substituted N-heterocycli
Stereoselective reductions with macrocyclic NADH models
Gran, Ulrik,Wennerstroem, Olof,Westman, Gunnar
, p. 3027 - 3040 (2000)
Macrocyclic NADH models with two (C2 symmetry) or four (D2 symmetry) nicotinamide units comprised in a ring have been prepared and found to reduce activated carbonyl compounds in good yields and high enantiomeric excess. The roles of magnesium ions as a cocatalyst and the temperature have also been investigated. The smaller, C2-symmetric macrocycle gave 96% ee upon reduction of ethyl benzoylformate whereas the best result with the larger D2-symmetric model was 81% ee for the reduction of methyl benzoylformate. (C) 2000 Elsevier Science Ltd.
Copper encapsulated alkaloids composite: An effective heterogeneous catalyst for electrocatalytic asymmetric hydrogenation
Yang, Heng-Pan,Fen, Qiu,Wang, Huan,Lu, Jia-Xing
, p. 38 - 42 (2016)
A novel heterogeneous catalyst, alkaloid@Cu was prepared by the entrapment of commercially purchased alkaloids within non-noble metallic copper nanoparticles. This composite was compacted into a coin and directly used as cathode for electrocatalytic asymmetric hydrogenation of aromatic ketones. Using water as hydrogen source, optically active alcohols with 71% ee value and 93% yield were obtained under very mild conditions.
Steric and electronic effects in the enantioselective hydrogenation of activated ketones on platinum: Directing effect of ester group
Diezi, Simon,Reimann, Sven,Bonalumi,Mallat, Tamas,Baiker, Alfons
, p. 255 - 262 (2006)
Steric effects in the Pt-catalyzed asymmetric hydrogenation of nine different α-ketoesters were studied by variation of the bulkiness at the keto and ester side of the substrates, and by using cinchonidine (CD), its 6′-methoxy derivative quinine, and o-ph
Stereocontrolled reduction of α- and β-keto esters with micro green algae, Chlorella strains
Ishihara, Kohji,Yamaguchi, Hitomi,Adachi, Noriko,Hamada, Hiroki,Nakajima, Nobuyoshi
, p. 2099 - 2103 (2000)
The stereocontrolled reduction of α- and β-keto esters using micro green algae was accomplished by a combination of the cultivation method and the introduction of an additive. The reduction of ethyl pyruvate and ethyl benzoylformate by the photoautotrophically cultivated Chlorella sorokiniana gave the corresponding alcohol in high e.e. (>99% e.e. (S) and >99% e.e. (R), respectively). In the presence of glucose as an additive, the reduction of ethyl 3-methyl-2-oxobutanoate by the heterotrophically cultivated C. sorokiniana afforded the corresponding (R)-alcohol. On the other hand, the reduction in the presence of ethyl propionate gave the (S)-alcohol. Ethyl 2-methyl-3-oxobutanoate was reduced in the presence of glycerol by the photoautotrophically cultivated C. sorokiniana or the heterotrophically cultivated C. sorokiniana to the corresponding syn-(2R,3S)-hydroxy ester with high diastereo- and enantiomeric excess (e.e.). Some additives altered the stereochemical course in the reduction of α- and β-keto esters.
Enzymatic enantioselective reduction of α-ketoesters by a thermostable 7α-hydroxysteroid dehydrogenase from Bacteroides fragilis
Zhu, Dunming,Stearns, Jennifer Elisabeth,Ramirez, Monica,Hua, Ling
, p. 4535 - 4539 (2006)
A thermostable 7α-hydroxysteroid dehydrogenase (7-HSDH) from Bacteroides fragilis ATCC 25285 was cloned and over-expressed in E. coli, and its substrate specificity and stereoselectivity toward reduction of various ketones were examined. This alcohol dehydrogenase was active toward a series of aromatic and bulky aliphatic α-ketoesters. The substituents at the phenyl ring of aromatic α-ketoesters greatly affected the activity, but their effects on enantioselectivity were minimal. The synthetic application of this enzyme was then demonstrated through the preparation of a few α-hydroxy carboxylic acid esters of pharmaceutical interest.
Enantioselective synthesis of ethyl (S)-2-hydroxy-4-phenylbutyrate by recombinant diketoreductase
Wu, Xuri,Wang, Yuchen,Ju, Jianming,Chen, Chen,Liu, Nan,Chen, Yijun
, p. 2504 - 2509 (2009)
Recombinant diketoreductase showed excellent stereoselectivity in the double reduction of β,δ-diketo esters. To investigate the substrate specificity and to broaden the applications of this new biocatalyst, a number of ketone substrates were used to evaluate the substrate spectrum and enantioselectivity of this enzyme in the present study. Among the ketone substrates tested, only this enzyme displayed high efficiency and excellent enantioselectivity in the reduction of ethyl 2-oxo-4-phenylbutyrate to ethyl (S)-2-hydroxy-4-phenylbutyrate. After optimizing the reaction conditions, the bio-reduction of ethyl 2-oxo-4-phenylbutyrate at a substrate concentration of 0.8 M (164.8 g/L) was achieved by the recombinant diketoreductase in an aqueous-toluene biphasic system coupled with formate dehydrogenase for the regeneration of cofactor, resulting in an overall hydroxyl product yield of 88.7% (99.5% ee). This new enzymatic transformation may offer a practical method for the preparation of this important chiral building block.
A homochiral porous metal-organic framework for enantioselective adsorption of mandelates and photocyclizaton of tropolone ethers
Peng, Yongwu,Gong, Tengfei,Cui, Yong
, p. 8253 - 8255 (2013)
A chiral porous metal-organic framework of an axially C2- symmetric 1,1′-biphenol ligand is constructed and can be used as a solid-state host to enanioselectively adsorb mandelates with up to 93.1% ee and to entrap achiral tropolone ethers and
