- Unraveling two pathways for NHPI-mediated electrocatalytic oxidation reaction
-
Two pathways for N-hydroxyphthalimide (NHPI)-mediated electrocatalytic oxidation using phenylacetate derivatives as template substrates were first reported for benzylic C[sbnd]H oxidation to oxygenated and non-oxygenated products. DFT calculation indicates that the hydrogen-atom transfer (HAT) process between phthalimido-N-oxyl (PINO) and substrate is a rate-determined step. Aromatic α-keto esters and 2-((1,3-dioxoisoindolin-2-yl)oxy)-2-aryl acetate obtained by cross-coupling between benzylic radical and PINO can be selectively synthesized through controlling the concentration of PINO radical. This method provides a deep understanding for selective weak C[sbnd]H oxidation using NHPI as redox mediator.
- Xu, Leitao,Yi, Yangjie,Hu, Sideng,Ye, Jiao,Hu, Aixi
-
-
- Tris(pentafluorophenyl)borane-Catalyzed Oxygen Insertion Reaction of α-Diazoesters (α-Diazoamides) with Dimethyl Sulfoxide
-
A tris(pentafluorophenyl)borane-catalyzed oxidation reaction of α-diazoesters (α-diazo amides) with dimethyl sulfoxide has been developed. The reaction proceeds under metal free conditions to afford a series α-ketoesters and α-ketoamides. The synthetic utility of this protocol is demonstrated through synthetic transformations and scaled-up synthesis. (Figure presented.).
- Gao, Wen-Xia,Liu, Miao-Chang,Wu, Hua-Yue,Wu, Xiao-Yang,Zhou, Yun-Bing
-
supporting information
(2022/01/19)
-
- Tandem Photoredox-Chiral Phosphoric Acid Catalyzed Radical-Radical Cross-Coupling for Enantioselective Synthesis of 3-Hydroxyoxindoles
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A photochemical protocol that couples diarylamines and α-ketoesters to afford the chiral 3-hydroxyoxindoles through tandem photoredox and chiral phosphoric acid catalysis is developed. The reaction involves an enantioselective photochemical radical-radical cross-coupling process. The chiral phosphoric acid is discovered to play crucial roles by decreasing the reductive potentials of α-ketoesters and stereocontrolling the downstream asymmetric radical-radical cross-coupling via the formation of pentacoordinate complex.
- Zhang, Yang,Ye, Dan,Shen, Lei,Liang, Kangjiang,Xia, Chengfeng
-
supporting information
p. 7112 - 7117
(2021/09/14)
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- Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide
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Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO2) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO2 to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S1) of the acylsilane and the addition to CO2 is not in a concerted manner.
- Fan, Zhengning,Yi, Yaping,Chen, Shenhao,Xi, Chanjuan
-
supporting information
p. 2303 - 2307
(2021/04/05)
-
- Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED
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We designed and prepared a series of methyl benzoylformate (MBF) derivatives Norrish type I photoinitiators (MBFs) for light-emitting diode (LED)-induced photopolymerization through computer simulation. The potential photolysis mechanism of MBFs under LED at 405 nm was explored by steady-state photolysis, nuclear magnetic resonance, and electron spin resonance. The as-synthesized photoinitiator dimethyl 1,4-dibenzoylformate (DM-BD-F) can efficiently initiate free radical photopolymerization of acrylate monomers under LED irradiation at 405 nm. Moreover, we predicted well the photoinitiating capability of MBFs through the cleavage exothermy (ΔH) calculated by triplet bond dissociation energy (BDE) and triplet energy (ET). Significantly, based on the weak absorption of MBFs at 405 nm, MBFs were successfully applied to deep-layer photocuring and the curing depth reached 6.5 cm after the irradiation of LED at 405 nm for 30 s. This research provides a new idea and efficient strategy for the molecular design of photoinitiators for deep-layer photocuring.
- He, Xianglong,Gao, Yanjing,Nie, Jun,Sun, Fang
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p. 3854 - 3864
(2021/05/07)
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- Photoinduced Diverse Reactivity of Diazo Compounds with Nitrosoarenes
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A diverse reactivity of diazo compounds with nitrosoarene in an oxygen-transfer process and a formal [2 + 2] cycloaddition is reported. Nitosoarene has been exploited as a mild oxygen source to oxidize an in situ generated carbene intermediate under visible-light irradiation. UV-light-mediated in situ generated ketenes react with nitosoarenes to deliver oxazetidine derivatives. These operationally simple processes exemplify a transition-metal-free and catalyst-free protocol to give structurally diverse α-ketoesters or oxazetidines.
- Roy, Sourav,Kumar, Gourav,Chatterjee, Indranil
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p. 6709 - 6713
(2021/09/08)
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- Amphiphilic fluorine-containing benzoyl formate photoinitiator suitable for LED photopolymerization and preparation method of amphiphilic fluorine-containing benzoyl formate photoinitiator
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The invention discloses an amphiphilic fluorine-containing benzoyl formate photoinitiator suitable for LED photopolymerization, relates to the field of photosensitive macromolecules, and aims to solve the problems that an existing photoinitiator is poor in initiation performance under the irradiation of an LED light source and limited in application in the field of deep polymerization. The chemical structural general formula of the photoinitiator is shown in the specification, wherein R1 is selected from hydrogen, C1-C16 aliphatic groups, aralkyl, ether and aryl, R2, R3, R4, R5 and R6 are selected from hydrogen, fluorine and trifluoromethyl, but R2, R3, R4, R5 and R6 cannot be hydrogen at the same time. The invention also provides a preparation method of the photoinitiator and application of the photoinitiator in a photopolymerization system. The photoinitiator has the beneficial effects that the photoinitiator has proper absorption capacity in a visible light region, not only ensures higher photopolymerization rate under an LED light source, but also can be applied to deep polymerization, in addition, the photoinitiator is suitable for oily and water-based photopolymerization systems, does not contain ions, is wider in application range, and facilitated the development of the LED photopolymerization industry.
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- Preparation method of alpha-ketoester compound
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The invention discloses a preparation method of an alpha-ketone ester compound. The method specifically comprises the following operation steps: adding raw materials alpha-diazo ester and an organic photocatalyst into a reaction flask, then adding an organic solvent, and reacting for 2-12 hours in air at room temperature under the irradiation of a visible light lamp; after the reaction is monitored by thin-layer chromatography (TLC), stopping the reaction, and extracting a reaction solution by using ethyl acetate; concentrating the extracting solution under reduced pressure to obtain a crude product, and performing column chromatography separation on the crude product to obtain the alpha-diazonium ester compound. According to the preparation method, clean visible light is used as reaction energy, cheap organic dye is used as a photocatalyst, air is used as a green oxidizing agent and an oxygen source, and the preparation method has the advantages of simplicity and convenience in operation, no metal residue and mild reaction conditions.
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-
Paragraph 0106-0109
(2021/04/21)
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- Preparation method for rapidly generating alpha-ketone ester through iodine-mediated alpha-diazonium ester oxidation
-
The invention relates to the field of research of ketone ester compounds, in particular to a preparation method for rapidly generating alpha-ketone ester through iodine-mediated alpha-diazo ester oxidation, the preparation method comprises the following steps: in an organic solvent, stirring alpha-diazo ester and iodine elementary substance as raw materials at room temperature for about half an hour to obtain the alpha-ketone ester compound. According to the method, transition metal does not need to be used as a catalyst, a strong oxidant does not need to be used, only under the room temperature condition, the low-toxicity and cheap iodine elementary substance is used as the oxidant, and the alpha-keto ester is generated through efficient oxidation of the alpha-diazonic acid ester. The method has the advantages that the reaction time is short (about 0.5 hour), the universality is high, the alpha-diazonic acid ester with electron donating groups or electron withdrawing groups can achieve medium to excellent yield (80%-99%), a greener alternative approach is represented, and a new general synthesis route is provided for efficient preparation of alpha-ketoester.
- -
-
Paragraph 0025; 0028-0029; 0031
(2021/07/24)
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- Stoichiometric Photochemical Carbene Transfer by Bamford–Stevens Reaction
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The photolysis of diazoalkanes is a timely strategy to conduct carbene-transfer reactions under mild and metal-free reaction conditions, and has developed as an important alternative to conventional metal-catalyzed carbene-transfer reactions. One of the major limitations lies within the rapidly occurring side reaction of the carbene intermediate with remaining diazoalkane molecules that result in the use of an excess of the reaction partner and thus impacts on the reaction efficiency. Herein, we describe a protocol that takes advantage of the in situ generation of donor–acceptor diazoalkanes by Bamford–Stevens reaction. Following this strategy, the concentration of the diazoalkane reaction partner can be minimized to reduce unwanted side reactions and to now conduct photochemical carbene transfer reactions under stoichiometric reaction conditions. We have explored this approach in the C?H and N?H functionalization and cyclopropanation reaction of N-heterocycles and could demonstrate the applicability of this method in 51 examples.
- Aseeva, Polina,Empel, Claire,Jana, Sripati,Koenigs, Rene M.,Li, Fang,Verspeek, Dennis
-
supporting information
p. 2586 - 2591
(2020/03/04)
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- Copper(I)-catalyzed aerobic oxidation of α-diazoesters
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A practical Cu-catalyzed oxidation of α-diazoesters to α-ketoesters using molecular oxygen as an oxidant has been developed. Both electron-poor and electron-rich aryl α-diazoesters are suitable substrates and provide the α-ketoesters in good yields. In this oxidative system, α-diazo-β-ketoesters are also compatible as substrates but unexpectedly furnish α-ketoesters via C-C bond cleavage, rather than the vicinal tricarbonyl products.
- Xu, Changming,Bai, Lei,Wang, Yongchang
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p. 12579 - 12584
(2020/11/09)
-
- Method for preparing spiro beta-lactam
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The invention discloses a method for preparing spiro beta-lactam. The method comprises the following step: carrying out [2+1] cyclization reaction on beta-lactam and keto ester under the condition ofa phosphine catalyst to generate spiro beta-lactam. The
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-
Paragraph 0048-0051
(2020/07/12)
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- CuO-catalyzed oxidation of aryl acetates with aqueous tert-butyl hydroperoxide for the synthesis of α-ketoesters
-
A practical method to access α-ketoesters from readily available aryl acetates is developed. In this approach, aqueous tert-butyl hydroperoxide and CuO are employed. No additional solvents are required and it was found that the peroxide side products in the reaction can be decomposed by pyridine.
- Jiang, Jin
-
p. 235 - 240
(2019/07/16)
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- Cobalt Nanoparticles Embedded in N-Doped Porous Carbon Derived from Bimetallic Zeolitic Imidazolate Frameworks for One-Pot Selective Oxidative Depolymerization of Lignin
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Cobalt nanoparticles embedded in N-doped porous carbon (Co@CN) were prepared by the pyrolysis of bimetallic zeolitic imidazolate frameworks (BMZIFs) based on ZIF-8 and ZIF-67. The catalyst shows excellent catalytic efficiency in one-pot selective oxidative cleavage of different linkages like β-O-4, a-O-4 and β-1 in organosolv lignin and lignin model compounds in the presence of oxygen (ambient pressure) under mild conditions (383 K). Compared with traditional supported catalyst, the catalyst gives a highly hollow structure, which favored the adsorption of substrates and oxygen. The uniform cobalt nanoparticles surrounded by N-doped graphitic structures and the strong electron transfer from graphitic nitrogen to Co NPs make it hard to be oxidized prior to use and higher catalytic reactivity. Moreover, the catalyst can be easily recovered by magnetic force after the reaction, and reused after reduction for five times without an obvious change in yields.
- Sun, Kangkang,Chen, Shujie,Zhang, Jiawei,Lu, Guo-Ping,Cai, Chun
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p. 1264 - 1271
(2019/02/01)
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- Reductive amination of ketonic compounds catalyzed by Cp*Ir(III) complexes bearing a picolinamidato ligand
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Cp*Ir complexes bearing a 2-picolinamide moiety serve as effective catalysts for the direct reductive amination of ketonic compounds to give primary amines under transfer hydrogenation conditions using ammonium formate as both the nitrogen and hydrogen source. The clean and operationally simple transformation proceeds with a substrate to catalyst molar ratio (S/C) of up to 20,000 at relatively low temperature and exhibits excellent chemoselectivity toward primary amines.
- Tanaka, Kouichi,Miki, Takashi,Murata, Kunihiko,Yamaguchi, Ayumi,Kayaki, Yoshihito,Kuwata, Shigeki,Ikariya, Takao,Watanabe, Masahito
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p. 10962 - 10977
(2019/09/03)
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- Cobalt-Catalyzed Transfer Hydrogenation of α-Ketoesters and N-Cyclicsulfonylimides Using H2O as Hydrogen Source
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A Co-catalyzed effective transfer hydrogenation of various α-ketoesters and N-cyclicsulfonylimides by safe and environmentally benign H2O as hydrogen source is described. The reaction used easily available and easy to handle zinc metal as a reductant. Interestingly, the catalytic system does not require ligand for reduction of N-cyclicsulfonylimides. (Figure presented.).
- Gao, Yang,Zhang, Xuexin,Laishram, Ronibala Devi,Chen, Jingchao,Li, Kangkui,Zhang, Keyang,Zeng, Guangzhi,Fan, Baomin
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supporting information
p. 3991 - 3997
(2019/08/02)
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- Design, synthesis and evaluation of novel diaryl-1,5-diazoles derivatives bearing morpholine as potent dual COX-2/5-LOX inhibitors and antitumor agents
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In this paper, 41 hybrid compounds containing diaryl-1,5-diazole and morpholine structures acting as dual COX-2/5-LOX inhibitors have been designed, synthesized and biologically evaluated. Most of them showed potent antiproliferative activities and COX-2/5-LOX inhibitory in vitro. Among them, compound A33 displayed the most potency against cancer cell lines (IC50 = 6.43–10.97 μM for F10, HeLa, A549 and MCF-7 cells), lower toxicity to non-cancer cells than celecoxib (A33: IC50 = 194.01 μM vs. celecoxib: IC50 = 97.87 μM for 293T cells), and excellent inhibitory activities on COX-2 (IC50 = 0.17 μM) and 5-LOX (IC50 = 0.68 μM). Meanwhile, the molecular modeling study was performed to position compound A33 into COX-2 and 5-LOX active sites to determine the probable binding models. Mechanistic studies demonstrated that compound A33 could block cell cycle in G2 phase and subsequently induced apoptosis of F10 cells. Furthermore, compound A33 could significantly inhibit tumor growth in F10-xenograft mouse model, and pharmacokinetic study of compound A33 indicated that it showed better stability in vivo. In general, compound A33 could be a promising candidate for cancer therapy.
- Li, Zhang,Wang, Zhong-Chang,Li, Xin,Abbas, Muhammad,Wu, Song-Yu,Ren, Shen-Zhen,Liu, Qi-Xing,Liu, Yi,Chen, Peng-Wen,Duan, Yong-Tao,Lv, Peng-Cheng,Zhu, Hai-Liang
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p. 168 - 184
(2019/03/17)
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- Method for catalyzing oxidative cracking of lignin by heterogeneous cobalt
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The invention discloses a method for catalyzing oxidative cracking of lignin by a heterogeneous cobalt. The method adopts a porous carbon-nitrogen-loaded cobalt nano-material as a catalyst, and oxidative cracking of beta-O-4, alpha-O-4 and beta-1 lignin template compounds and solvent type lignin is carried out under the action of the catalyst with methanol as a solvent and oxygen as an oxidant inorder to obtain phenol, methyl benzoate and other small molecule compounds. The heterogeneous cobalt catalyst adopted in the invention realizes a wide application range of a substrate, is suitable forthe oxidative cracking of the beta-O-4, alpha-O-4 and beta-1 lignin template compounds and solvent type lignin, realizes high yield of a product and no polymerization of the product, and can be simply recovered through magnetic force after the reaction ends.
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-
Paragraph 0024; 0025; 0026
(2018/11/26)
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- Umpolung Reactivity of Aldehydes toward Carbon Dioxide
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Carbon dioxide is an intrinsically stable molecule. Therefore, its activation requires extra energy input in the form of reactive reagents and/or activated catalysts and, often, harsh reaction conditions. Reported here is a direct carboxylation reaction of aromatic aldehydes with carbon dioxide to afford α-keto acids as added-value products. In situ generation of a reactive cyanohydrin was the key to the successful carboxylation reaction under operationally mild reaction conditions (25–40 °C, 1 atm CO2). The resulting α-keto acids served as a platform for α-amino acid synthesis by reductive amination reactions, illustrating the chemical synthesis of essential bioactive molecules from carbon dioxide.
- Juhl, Martin,Lee, Ji-Woong
-
supporting information
p. 12318 - 12322
(2018/09/10)
-
- Anti-Selective Catalytic Asymmetric Nitroaldol Reaction of α-Keto Esters: Intriguing Solvent Effect, Flow Reaction, and Synthesis of Active Pharmaceutical Ingredients
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A rare-earth metal/alkali metal bimetallic catalyst proved particularly effective for enantioselectively coupling nitroalkanes and α-keto esters in an anti-selective manner to afford synthetically versatile, densely functionalized, and optically active α-nitro tertiary alcohols. A chiral diamide ligand captured two distinct metal cations, giving rise to a catalytically competent solid-phase heterobimetallic catalyst by simple mixing via self-assembly. The advantage of the solid-phase asymmetric catalyst was realized by successful application to the enantio- and diastereoselective reaction in a continuous-flow platform. The use of closely related solvents in terms of structures and polarity parameters, THF and its methylated congener 2-Me-THF, had an unexpectedly large solvent effect both on the reaction rate and the stereoselectivity. The nitroaldol products share a privileged unit for active pharmaceutical ingredients, as demonstrated by the streamlined enantioselective synthesis of the marketed antifungal agents efinaconazole and albaconazole.
- Karasawa, Tomoya,Oriez, Rapha?l,Kumagai, Naoya,Shibasaki, Masakatsu
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supporting information
p. 12290 - 12295
(2018/09/27)
-
- Visible Light Promotes Decyanation Esterification Reaction of β - Ketonitriles with Dioxygen and Alcohols to α-Ketoesters
-
A green and mild method has been developed for the conversion of β-ketonitriles into α-ketoesters under catalyst-free conditions. A plausible mechanism is that visible light promotes singlet oxygen generation to form the products through oxidative C-H bond functionalization and C-C σ -bond cleavage.
- Xu, Chen,Zhang, Nan-Nan,Li, Xiao-Ji,Ge, Yan-Qin,Diao, Pin-Hui,Guo, Cheng
-
supporting information
p. 1065 - 1070
(2018/05/01)
-
- I 2 /TBHP-Promoted Approach to α-Keto Esters from Trifluoromethyl β-Diketones and Alcohols via C-C Bond Cleavage
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A metal-free oxidative coupling reaction of trifluoromethyl β-diketones with alcohols for the synthesis of α-keto esters in good to excellent yields has been developed. Preliminary mechanistic studies suggest that an I 2 /TBHP promoted sequential iodination, C-C bond cleavage, C-O bond formation and oxidation pathway is involved in this reaction.
- Shao, Tongle,Fang, Xiang,Zhou, Jun,Jin, Chen,Yang, Xueyan,Wu, Fanhong
-
supporting information
p. 2018 - 2023
(2017/09/13)
-
- Iridium-Catalyzed Asymmetric Hydrogenation of Unsaturated Piperazin-2-ones
-
Two different iridium catalyst systems, generated from the ruthenocene-based phosphine-oxazoline ligand tBu-mono-RuPHOX or the diphosphine ligand BINAP, were developed for the asymmetric hydrogenation of 5,6-dihydropyrazin-2(1H)-ones, affording chiral piperazin-2-ones in good yields and with moderate to good ees. Different catalytic behaviors for the hydrogenation of these types of substrate were observed with these two catalyst systems. Our tBu-mono-RuPHOX ligand, which bears a ruthenocene scaffold with planar chirality, was found to be the best ligand for the [Ir(L)(COD)]BArF catalyst system, affording the desired products with up to 94% ee. (Figure presented.).
- Wang, Yanzhao,Liu, Yuanyuan,Li, Kun,Yang, Guoqiang,Zhang, Wanbin
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supporting information
p. 1933 - 1941
(2017/06/09)
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- Enantioselective Iridium-Catalyzed Hydrogenation of α-Keto Amides to α-Hydroxy Amides
-
A highly enantioselective iridium-catalyzed hydrogenation of α-keto amides to form α-hydroxy amides has been achieved with excellent results (up to >99% conversion and up to >99% ee, TON up to 100?000). As an example, this protocol was applied to the synthesis of (S)-4-(2-amino-1-hydroxyethyl)benzene-1,2-diol, the enantiomer of norepinephrine, which is widely used as an injectable drug for the treatment of critically low blood pressure. Density functional theory (DFT) calculations were also carried out to reveal the reaction mechanism.
- Gu, Guoxian,Yang, Tilong,Yu, Ouran,Qian, Hua,Wang, Jiang,Wen, Jialin,Dang, Li,Zhang, Xumu
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supporting information
p. 5920 - 5923
(2017/11/10)
-
- Rh-catalyzed asymmetric hydrogenation of racemic aldimines via dynamic kinetic resolution
-
Catalyzed by a rhodium complex of P-stereogenic diphosphine ligand trichickenfootphos (TCFP), asymmetric hydrogenation of racemic aldimines via dynamic kinetic resolution has been realized for the preparation of chiral arylglycines with good yields and enantioselectivities.
- Fan, Dongyang,Lu, Jian,Liu, Yang,Zhang, Zhenfeng,Liu, Yangang,Zhang, Wanbin
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p. 5541 - 5547
(2016/08/05)
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- First Iridium-Catalyzed Highly Enantioselective Hydrogenation of β-Nitroacrylates
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The first highly chemo- and enantioselective hydrogenation of β-nitroacrylates was accomplished with an iridium catalyst (Ir-4) with yields and enantioselectivities of up to 96% and 98% ee, respectively. The resulting α-chiral β-nitro propionates are attractive building blocks for the synthesis of chiral β2-amino acids, which are the core scaffolds of bioactive natural products, pharmaceuticals, and β-peptides.
- Li, Shengkun,Xiao, Taifeng,Li, Dangdang,Zhang, Xumu
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p. 3782 - 3785
(2015/08/18)
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- 2-Oxo promoted hydrophosphonylation & aerobic intramolecular nucleophilic displacement reaction
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Highly efficient catalyst free methods for the synthesis of α-hydroxy-β-oxophosphonates and α-oxoesters have been described. The existence of a 2-oxo group in α-oxoaldehydes is a key factor in promoting the reaction of the tervalent phosphite form towards 2-oxoaldehydes in the synthesis of α-hydroxy-β-oxophosphonates. The in situ activated α-C-H atom of α-hydroxy-β-oxophosphonates sustains aerobic intramolecular nucleophilic displacement in a curious way to produce α-oxoester.
- Battula, Satyanarayana,Battini, Narsaiah,Singh, Deepika,Ahmed, Qazi Naveed
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supporting information
p. 8637 - 8641
(2015/08/24)
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- QUINOXALINE COMPOUNDS AND USES THEREOF
-
This invention provides compounds of formula I and subsets thereof: wherein T, J, R, R4, Rq, o, RA, and RB and subsets thereof are as described in the specification. The compounds are inhibitors of NAMPT and are thus useful for treating cancer, inflammatory conditions, or T-cell mediated autoimmune disease.
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Paragraph 00332
(2015/11/09)
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- Metal-free tandem oxidative aryl migration and C-C bond cleavage: Synthesis of α-ketoamides and esters from acrylic derivatives
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A novel tandem metal-free oxidative aryl migration/C-C bond-cleavage reaction, mediated by hypervalent iodine reagent, has been discovered. The presented transformation provided straightforward access to important α-ketoamide and α-ketoester derivatives from readily available acrylic derivatives via a concerted process of 1,2-aryl shift concomitant with C-C bond cleavage.
- Liu, Le,Du, Liang,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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supporting information
p. 5772 - 5775
(2015/02/19)
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- An umpolung approach toward N-aryl nitrone construction: A phosphine-mediated addition of 1,2-dicarbonyls to nitroso electrophiles
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An umpolung approach toward nitrone construction utilizing a phosphine-mediated addition of 1,2-dicarbonyls to nitroso compounds is reported. The reaction exhibits a high degree of chemoselectivity and provides direct access to isoxazolidines, imines, and
- Chavannavar, Aditi P.,Oliver, Allen G.,Ashfeld, Brandon L.
-
supporting information
p. 10853 - 10856
(2014/10/16)
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- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
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A new efficient and highly enantioselective direct asymmetric hydrogenation of α-keto acids employing the Ir/SpiroPAP catalyst under mild reaction conditions has been developed. This method might be feasible for the preparation of a series of chiral α-hydroxy acids on a large scale.
- Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
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supporting information
p. 15987 - 15990
(2015/02/19)
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- Electrochemical synthesis of the aryl α-ketoesters from acetophenones mediated by Ki
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Two C-O bonds formed in one step: The oxidative coupling reaction of acetophenones with alcohol was developed by a dioxygen activation to afford α-ketoesters under electrochemical conditions. This novel transformation not only provides a simple and efficient approach to synthetize α-ketoester derivatives, but also invents a new strategy to construct a C-O bond by virtue of an anode oxidation (see scheme). Copyright
- Zhang, Zhenlei,Su, Jihu,Zha, Zhenggen,Wang, Zhiyong
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supporting information
p. 17711 - 17714
(2014/01/17)
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- An efficient and practical synthesis of aryl and hetaryl α-keto esters
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A general and highly efficient method was developed for the synthesis of -keto esters by oxidative esterification of 2,2-dibromo-1-(het)arylethanones by sequential treatment with dimethyl sulfoxide and an alkanol. The versatility of the reaction was established by synthesizing a range of -keto esters by treatment of 2,2-dibromoethanones, derived from aryl or hetaryl ketones, with di-methyl sulfoxide and a cyclic or acyclic primary or secondary alcohol. The mechanism of the reaction was established by means of a detailed study. Georg Thieme Verlag Stuttgart · New York.
- Raghunadh, Akula,Meruva, Suresh Babu,Kumar, Nuka Anil,Kumar, Gudla Santosh,Rao, L. Vaikunta,Syamkumar
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supporting information; experimental part
p. 283 - 289
(2012/03/26)
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- One-pot efficient synthesis of aryl α-keto esters from aryl-ketones
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A novel one-pot synthesis of aryl α-keto esters was developed through oxidation of aryl-ketones using selenium dioxide, esterification accompanied by ketalization, and hydrolysis. Both aromatics and heteroaromatics gave good yields by this one-pot method.
- Zhuang, Jing,Wang, Changqing,Xie, Fang,Zhang, Wanbin
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experimental part
p. 9797 - 9800
(2010/02/27)
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- Facile synthesis of aryl α-keto esters via the reaction of aryl diazoacetate with H2O and DEAD
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A facile synthesis of aryl aα-keto esters in high yields is reported involving the reaction of aryl diazoacetate with H2O and diethyl azodicarboxylate (DEAD) catalyzed by dirhodium acetate. Georg Thieme Verlag Stuttgart.
- Guo, Zhenqiu,Huang, Haoxi,Fu, Qingquan,Hu, Wenhao
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p. 2486 - 2488
(2008/02/11)
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- New approach to biomimetic transamination using bifunctional [1,3]-proton transfer catalysis in thioxanthenyl dioxide imines
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A pyridoxamine equivalent, 9-aminothioxanthene 10,10-dioxide, has been designed that is capable of affording transamination in good to excellent yields of natural as well as artificial amino acids. Amidines and guanidines in catalytic amounts were capable of performing [1,3]-proton transfer in the imines under mild conditions, whereas various simple amines failed. The use of chiral catalysts resulted in modest asymmetric induction (ee ≤ 45%). The electronic dependence in para-substituted phenyl glyoxylate imines, isotope effects, and computational studies support a stepwise, bifunctional mechanism for amidine and guanidine catalysts. Attempts toward an autocatalytic model system are described.
- Hjelmencrantz, Anders,Berg, Ulf
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p. 3585 - 3594
(2007/10/03)
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- Pyrrolidine modulators of chemokine receptor activity
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The present invention is directed to pyrrolidine compounds of the formula 1: (wherein R1, R2, R3, R4, R5, R6and n are defined herein) which are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-5 and/or CCR-3.
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- Facile Synthesis of α-Keto Carbonyl Compounds by Indirect Anodic Oxidation
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Secondary alcohols having a carbonyl group at the neighboring carbon atom were electrochemically oxidized to the corresponding α-keto carbonyl compounds in good yields.Thus, aromatic α-hydroxyl esters were easily transformed to arylglyoxylates in excellent yields using an undivided cell while efficient anodic oxidation of α-hydroxyl ketones and aliphatic α-hydroxyl esters successfully proceeded in a divided cell to give the corresponding α-keto carbonyl compounds.
- Maekawa, Hirofumi,Ishino, Yoshio,Nishiguchi, Ikuzo
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p. 1017 - 1020
(2007/10/02)
-