27854-88-2Relevant academic research and scientific papers
Bioconversion of optically active pyridyl alcohols from the corresponding racemates with plant cell cultures
Takemoto, Masumi,Achiwa, Kazuo
, p. 577 - 580 (1998)
A novel method for producing optically active pyridyl alcohols from the corresponding racemates was developed. When racemic pyridyl alcohol is incubated with Catharanthus roseus cell cultures, chiral alcohol is obtained in high yield with excellent enantiomeric excess (ee) (deracemization of racemate). Furthermore, the kinetic resolution of racetalc pyridyl alcohol via oxidation gave the chiral compound with high ee.
Deracemization of racemic 4-pyridyl-1-ethanol by Catharanthus roseus cell cultures
Takemoto, Masumi,Achiwa, Kazuo
, p. 1627 - 1629 (1998)
Immobilized cells of Catharanthus roseus synthesized (R)-4-pyridyl-1- ethanol from the corresponding racemate in 100% yield by stereoinversion of the (S)-alcohol in the racemate to the (R)-alcohol. Furthermore, in the reduction of 4-acetylpyridine, we could synthesize both (R) and (S)-4- pyridyl-1-ethanol during a short or a long incubation.
The synthesis of optically active pyridyl alcohols from the corresponding racemates by Catharanthus roseus cell cultures
Takemoto,Achiwa
, p. 2925 - 2928 (1995)
A novel method for producing optically active pyridyl alcohols 1a-f from the corresponding racemates was developed. When racemic 3-pyridylphenylmethanol 1b is reacted with Catharanthus roseus cell cultures, (-)-1b is obtained in 96% yield with 100% ee.
Amino Acid-Functionalized Metal-Organic Frameworks for Asymmetric Base–Metal Catalysis
Newar, Rajashree,Akhtar, Naved,Antil, Neha,Kumar, Ajay,Shukla, Sakshi,Begum, Wahida,Manna, Kuntal
, p. 10964 - 10970 (2021/03/29)
We report a strategy to develop heterogeneous single-site enantioselective catalysts based on naturally occurring amino acids and earth-abundant metals for eco-friendly asymmetric catalysis. The grafting of amino acids within the pores of a metal-organic framework (MOF), followed by post-synthetic metalation with iron precursor, affords highly active and enantioselective (>99 % ee for 10 examples) catalysts for hydrosilylation and hydroboration of carbonyl compounds. Impressively, the MOF-Fe catalyst displayed high turnover numbers of up to 10 000 and was recycled and reused more than 15 times without diminishing the enantioselectivity. MOF-Fe displayed much higher activity and enantioselectivity than its homogeneous control catalyst, likely due to the formation of robust single-site catalyst in the MOF through site-isolation.
Chiral Iron(II)-Catalysts within Valinol-Grafted Metal-Organic Frameworks for Enantioselective Reduction of Ketones
Akhtar, Naved,Antil, Neha,Begum, Wahida,Chauhan, Manav,Kumar, Ajay,Manna, Kuntal,Newar, Rajashree
, p. 10450 - 10459 (2021/08/31)
The development of highly efficient and enantioselective heterogeneous catalysts based on earth-abundant elements and inexpensive chiral ligands is essential for environment-friendly and economical production of optically active compounds. We report a strategy of synthesizing chiral amino alcohol-functionalized metal-organic frameworks (MOFs) to afford highly enantioselective single-site base-metal catalysts for asymmetric organic transformations. The chiral MOFs (vol-UiO) were prepared by grafting of chiral amino alcohol such as l-valinol within the pores of aldehyde-functionalized UiO-MOFs via formation of imine linkages. The metalation of vol-UiO with FeCl2 in THF gives amino alcohol coordinated octahedral FeII species of vol-FeCl(THF)3 within the MOFs as determined by X-ray absorption spectroscopy. Upon activation with LiCH2SiMe3, vol-UiO-Fe catalyzed hydrosilylation and hydroboration of a range of aliphatic and aromatic carbonyls to afford the corresponding chiral alcohols with enantiomeric excesses up to 99%. Vol-UiO-Fe catalysts have high turnover numbers of up to 15 ?000 and could be reused at least 10 times without any loss of activity and enantioselectivity. The spectroscopic, kinetic, and computational studies suggest iron-hydride as the catalytic species, which undergoes enantioselective 1,2-insertion of carbonyl to give an iron-alkoxide intermediate. The subsequent σ-bond metathesis between Fe-O bond and Si-H bond of silane produces chiral silyl ether. This work highlights the importance of MOFs as the tunable molecular material for designing chiral solid catalysts based on inexpensive natural feedstocks such as chiral amino acids and base-metals for asymmetric organic transformations.
Ruthenium-catalyzed hydrogenation of aromatic ketones using chiral diamine and monodentate achiral phosphine ligands
Wang, Mengna,Zhang, Ling,Sun, Hao,Chen, Qian,Jiang, Jian,Li, Linlin,Zhang, Lin,Li, Li,Li, Chun
, (2021/03/24)
The Ru-catalyzed asymmetric hydrogenation of ketones with chiral diamine and monodentate achiral phosphine has been developed. A wide range of ketones were hydrogenated to afford the corresponding chiral secondary alcohols in good to excellent enantioselectivities (up to 98.1% ee). In addition, an appropriate mechanism for the asymmetric hydrogenation was proposed and verified by NMR spectroscopy.
An Enantioconvergent Benzylic Hydroxylation Using a Chiral Aryl Iodide in a Dual Activation Mode
Abazid, Ayham H.,Clamor, Nils,Nachtsheim, Boris J.
, p. 8042 - 8048 (2020/09/21)
The application of a triazole-substituted chiral iodoarene in a direct enantioselective hydroxylation of alkyl arenes is reported. This method allows the rapid synthesis of chiral benzyl alcohols in high yields and stereocontrol, despite its nontemplated nature. In a cascade activation consisting of an initial irradiation-induced radical C-H-bromination and a consecutive enantioconvergent hydroxylation, the iodoarene catalyst has a dual role. It initiates the radical bromination in its oxidized state through an in-situ-formed bromoiodane and in the second, Cu-catalyzed step, it acts as a chiral ligand. This work demonstrates the ability of a chiral aryl iodide catalyst acting both as an oxidant and as a chiral ligand in a highly enantioselective C-H-activating transformation. Furthermore, this concept presents an enantioconvergent hydroxylation with high selectivity using a synthetic catalyst.
C1-Symmetric PNP Ligands for Manganese-Catalyzed Enantioselective Hydrogenation of Ketones: Reaction Scope and Enantioinduction Model
Zeng, Liyao,Yang, Huaxin,Zhao, Menglong,Wen, Jialin,Tucker, James H. R.,Zhang, Xumu
, p. 13794 - 13799 (2020/11/30)
A family of ferrocene-based chiral PNP ligands is reported. These tridentate ligands were successfully applied in Mn-catalyzed asymmetric hydrogenation of ketones, giving high enantioselectivities (92%～99% ee for aryl alkyl ketones) as well as high efficiencies (TON up to 2000). In addition, dialkyl ketones could also be hydrogenated smoothly. Manganese intermediates that might be involved in the catalytic cycle were analyzed. DFT calculation was carried out to help understand the chiral induction model. The Mn/PNP catalyst could discriminate two groups with different steric properties by deformation of the phosphine moiety in the flexible 5-membered ring.
RETRACTED ARTICLE: The Manganese(I)-Catalyzed Asymmetric Transfer Hydrogenation of Ketones: Disclosing the Macrocylic Privilege
Passera, Alessandro,Mezzetti, Antonio
supporting information, p. 187 - 191 (2019/12/11)
The bis(carbonyl) manganese(I) complex [Mn(CO)2(1)]Br (2) with a chiral (NH)2P2 macrocyclic ligand (1) catalyzes the asymmetric transfer hydrogenation of polar double bonds with 2-propanol as the hydrogen source. Ketones (43 substrates) are reduced to alcohols in high yields (up to >99 %) and with excellent enantioselectivities (90–99 % ee). A stereochemical model based on attractive CH–π interactions is proposed.
Efficient Asymmetric Synthesis of Ethyl (S)-4-Chloro-3-hydroxybutyrate Using Alcohol Dehydrogenase SmADH31 with High Tolerance of Substrate and Product in a Monophasic Aqueous System
Chen, Rong,Liu, Qinghai,Wang, Hualei,Wei, Dongzhi,Xie, Youyu,Yang, Zeyu,Ye, Wenjie
, p. 1068 - 1076 (2020/07/06)
Bioreductions catalyzed by alcohol dehydrogenases (ADHs) play an important role in the synthesis of chiral alcohols. However, the synthesis of ethyl (S)-4-chloro-3-hydroxybutyrate [(S)-CHBE], an important drug intermediate, has significant challenges concerning high substrate or product inhibition toward ADHs, which complicates its production. Herein, we evaluated a novel ADH, SmADH31, obtained from the Stenotrophomonas maltophilia genome, which can tolerate extremely high concentrations (6 M) of both substrate and product. The coexpression of SmADH31 and glucose dehydrogenase from Bacillus subtilis in Escherichia coli meant that as much as 660 g L-1 (4.0 M) ethyl 4-chloroacetoacetate was completely converted into (S)-CHBE in a monophasic aqueous system with a >99.9% ee value and a high space-time yield (2664 g L-1 d-1). Molecular dynamics simulation shed light on the high activity and stereoselectivity of SmADH31. Moreover, five other optically pure chiral alcohols were synthesized at high concentrations (100-462 g L-1) as a result of the broad substrate spectrum of SmADH31. All these compounds act as important drug intermediates, demonstrating the industrial potential of SmADH31-mediated bioreductions.
