- 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)
-
- Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED
-
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
-
p. 3854 - 3864
(2021/05/07)
-
- Silyl Cyanopalladate-Catalyzed Friedel-Crafts-Type Cyclization Affording 3-Aryloxindole Derivatives
-
3-Aryloxindole derivatives were synthesized through a Friedel-Crafts-type cyclization. The reaction was catalyzed by a trimethylsilyl tricyanopalladate complex generated in situ from trimethylsilyl cyanide and Pd(OAc) 2. Wide varieties of diethyl phosphates derived from N -arylmandelamides were converted almost quantitatively into oxindoles. When N, N -dibenzylamide was used instead of an anilide substrate, a benzo-fused δ-lactam was obtained. An oxindole product was subjected to substitution reactions to afford 3,3-diaryloxindoles with two different aryl groups.
- Ece, Hamdiye,Tange, Yuji,Yurino, Taiga,Ohkuma, Takeshi
-
supporting information
p. 935 - 939
(2021/02/22)
-
- Copper on charcoal: Cu0nanoparticle catalysed aerobic oxidation of α-diazo esters
-
By using a charcoal supported nano Cu0catalyst (Cu/C), a highly efficient oxidation of α-diazo esters to α-ketoesters with molecular oxygen as the sole oxidant has been developed. In the presence of the Cu/C catalyst, 2-aryl-α-diazo esters with both electron-donating and electron-withdrawing groups can be oxidized to the corresponding α-ketoesters efficiently. Furthermore, this Cu/C catalyst can catalyse the reaction of aryl α-diazo ester with water to form aryl ketoester, 2-aryl-2-hydroxyl acetate ester and 2-aryl acetate ester. In this case, water is split by α-diazo ester, and the diazo group is displaced by the oxygen or hydrogen atom in water. Mechanistic investigation showed that the reaction of α-diazo ester with oxygen proceeds through a radical pathway. In the presence of 2,2,6,6-tetramethyl piperidine nitrogen oxide, the reaction of α-diazo ester with oxygen is dramatically inhibited. Furthermore, the reaction of α-diazo ester with water is investigated by an isotopic tracer method, and GCMS detection showed that a disproportionation reaction occurred between α-diazo ester and water.
- Chu, Changhu,Dong, Wenwen,Lin, Jia,Teng, Jiangge,Wang, Zhiwei,Zhao, Rong
-
p. 6120 - 6126
(2021/07/21)
-
- Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide
-
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
-
p. 2303 - 2307
(2021/04/05)
-
- Preparation method of alpha-ketoester compound
-
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.
- -
-
Paragraph 0094-0097
(2021/04/21)
-
- Stoichiometric Photochemical Carbene Transfer by Bamford–Stevens Reaction
-
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)
-
- Novel methyl benzoylformate photoinitiator and preparation method thereof
-
The invention relates to the technical field of organic synthesis, in particular to a novel methyl benzoylformate photoinitiator and a preparation method thereof. The emission wavelength range of LEDlight sources used in the market at present is 365 nm or above, while, the maximum absorption wavelength of a traditional photoinitiator MBF is 255 nm, and as a result, the wavelength of the traditional photoinitiator MBF is not matched with the emission wavelength of the LED light sources. In order to enable the maximum absorption wavelength of the MBF photoinitiator to be matched with the main emission wavelength range of the LED light sources, the invention provides the novel methyl benzoylformate photoinitiator and the preparation method thereof. The compound is obtained by condensation reaction of a carbonyl functionalized methyl benzoylformate derivative containing double alpha H and a ketone compound; the maximum absorption wavelength of the compound can reach 365 nm or above; and the compound is matched with the LED light sources used on the market and has good commercial application prospects.
- -
-
Paragraph 0038; 0041; 0053; 0056
(2020/09/09)
-
- Novel synthesis method of alpha-carbonyl acid ester
-
The invention discloses a novel synthesis method of alpha-carbonyl acid ester. The method comprises the following steps: carrying out chlorination reaction on an alpha-methylene-containing nitrile compound and chlorine to obtain dichloronitrile, reacting the dichloronitrile product in a sulfuric acid and water system to obtain formyl cyanide, then acquiring an imino sulfate compound in the same reaction system, and finally performing esterification to obtain the target product. The adopted reaction raw materials are wide in sources and low in price, highly toxic solid sodium cyanide can be prevented from being used in the prior art, the method is environmentally friendly, and the method is easy to operate, mild in condition and easy to industrialize.
- -
-
Paragraph 0016; 0056; 0060-0061
(2020/07/21)
-
- Cobalt-Catalyzed Transfer Hydrogenation of α-Ketoesters and N-Cyclicsulfonylimides Using H2O as Hydrogen Source
-
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
-
supporting information
p. 3991 - 3997
(2019/08/02)
-
- Design, synthesis and evaluation of novel diaryl-1,5-diazoles derivatives bearing morpholine as potent dual COX-2/5-LOX inhibitors and antitumor agents
-
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
-
p. 168 - 184
(2019/03/17)
-
- Cobalt Nanoparticles Embedded in N-Doped Porous Carbon Derived from Bimetallic Zeolitic Imidazolate Frameworks for One-Pot Selective Oxidative Depolymerization of Lignin
-
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
-
p. 1264 - 1271
(2019/02/01)
-
- Method for catalyzing oxidative cracking of lignin by heterogeneous cobalt
-
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.
- -
-
Paragraph 0024; 0025; 0026
(2018/11/26)
-
- Copper-Catalysed (Diacetoxyiodo)benzene-Promoted Aerobic Esterification Reaction: Synthesis of Oxamates from Acetoacetamides
-
A copper-catalysed (diacetoxyiodo)benzene-promoted aerobic esterification reaction of acetoacetamides was developed for the synthesis of oxamates, which are useful precursors in synthetic organic chemistry. This practical and mild synthetic approach proceeded at 25 °C under open-air conditions and afforded methyl 2-oxo-2-(phenylamino)acetates in good to excellent yields combined with C?C σ-bond cleavage and formal oxidative C?H bond functionalization. A mechanism is proposed. (Figure presented.).
- Zhang, Zhiguo,Gao, Xiaolong,Yu, Haifeng,Zhang, Guisheng,Liu, Jianming
-
supporting information
p. 3406 - 3411
(2018/07/31)
-
- CuCl/TMEDA/nor-AZADO-catalyzed aerobic oxidative acylation of amides with alcohols to produce imides
-
Although aerobic oxidative acylation of amides with alcohols would be a good complement to classical synthetic methods for imides (e.g., acylation of amides with activated forms of carboxylic acids), to date, there have been no reports on oxidative acylation to produce imides. In this study, we successfully developed, for the first time, an efficient method for the synthesis of imides through aerobic oxidative acylation of amides with alcohols by employing a CuCl/TMEDA/nor-AZADO catalyst system (TMEDA = teramethylethylendiamine; nor-AZADO = 9-azanoradamantane N-oxyl). The proposed acylation proceeds through the following sequential reactions: aerobic oxidation of alcohols to aldehydes, nucleophilic addition of amides to the aldehydes to form hemiamidal intermediates, and aerobic oxidation of the hemiamidal intermediates to give the corresponding imides. This catalytic system utilizes O2 as the terminal oxidant and produces water as the sole by-product. An important point for realizing this efficient acylation system is the utilization of a TMEDA ligand, which, to the best of our knowledge, has not been employed in previously reported Cu/ligand/N-oxyl systems. Based on experimental evidence, we consider that plausible roles of TMEDA involve the promotion of both hemiamidal oxidation and regeneration of an active CuII-OH species from a CuI species. Here promotion of hemiamidal oxidation is particularly important. Employing the proposed system, various types of structurally diverse imides could be synthesized from various combinations of alcohols and amides, and gram-scale acylation was also successful. In addition, the proposed system was further applicable to the synthesis of α-ketocarbonyl compounds (i.e., α-ketoimides, α-ketoamides, and α-ketoesters) from 1,2-diols and nucleophiles (i.e., amides, amines, and alcohols).
- Kataoka, Kengo,Wachi, Keiju,Jin, Xiongjie,Suzuki, Kosuke,Sasano, Yusuke,Iwabuchi, Yoshiharu,Hasegawa, Jun-Ya,Mizuno, Noritaka,Yamaguchi, Kazuya
-
p. 4756 - 4768
(2018/06/07)
-
- Anti-Selective Catalytic Asymmetric Nitroaldol Reaction of α-Keto Esters: Intriguing Solvent Effect, Flow Reaction, and Synthesis of Active Pharmaceutical Ingredients
-
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
-
p. 12290 - 12295
(2018/09/27)
-
- A method for synthesis of α - keto ester
-
A synthetic method of [alpha]-keto ester. The invention relates to the technical field of chemical synthesis. The synthetic method comprises a step of in a solvent, with benzene seleninic acid as a catalyst and air as an oxidizing agent, oxidizing [alpha]-hydroxy acid ester to obtain an oxidized product [alpha]-keto ester. In the method, air is employed as the oxidizing agent, which is clean, is easy to obtain, and is harmless to environment. The method employs the benzene seleninic acid as the catalyst instead of a metal catalyst, so that the [alpha]-keto ester is metabolizable in human body and is ecological friendly since selenium is required microelement of living bodies. The synthetic method is carried out under mild conditions and is less in damage on devices. A system for the method is durable, so that the method is suitable for industrial production.
- -
-
Paragraph 0036-0038
(2017/08/25)
-
- I 2 /TBHP-Promoted Approach to α-Keto Esters from Trifluoromethyl β-Diketones and Alcohols via C-C Bond Cleavage
-
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
-
supporting information
p. 1933 - 1941
(2017/06/09)
-
- Copper-catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates: Synthesis of aryl/heteroaryl α-keto esters
-
A copper catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates is described for the first time. This transformation represents a new route to synthesize α-keto esters, which are important intermediates for pharmaceuticals and organic synthesis. The reaction proceeds via in situ generation of a thionium ion that undergoes hydrolysis to furnish α-keto esters in synthetically viable yields (up to 82%).
- Saha, Pipas,Ray, Sumit Kumar,Singh, Vinod K.
-
p. 1765 - 1769
(2017/04/13)
-
- Development of a simple system for the oxidation of electron-rich diazo compounds to ketones
-
Mild heating of diazo compounds in DMSO furnishes ketone products in moderate to excellent yields. The reaction is particularly effective on electron-rich substrates and exhibits high chemoselectivity, allowing for the use of diazo compounds containing additional oxidation-prone functional groups. This straightforward protocol offers an alternate route to synthetically useful α-ketoesters from readily available aryl diazoacetates.
- O'Connor, Nicholas R.,Bolgar, Peter,Stoltz, Brian M.
-
p. 849 - 851
(2016/02/05)
-
- 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
-
p. 5541 - 5547
(2016/08/05)
-
- In Situ Generated AgII-Catalyzed Selective Oxo-Esterification of Alkyne with Alcohol to α-Ketoester: Photophysical Study
-
An expert and easy one-step catalytic method for the multi O-C coupling of alkyne is developed for the synthesis of valuable α-ketoesters and their chiral analogues, in contrast to the generation of esters by a noncatalytic method. The in situ generated powerful AgII catalyst from AgOTf is the workhorse in the oxidative grafting of alkyne with PhIO and alcohol. The radical mechanism is confirmed in our controlled experiments and UV-vis study.
- Laha, Radha M.,Khamarui, Saikat,Manna, Saikat K.,Maiti, Dilip K.
-
supporting information
p. 144 - 147
(2016/01/12)
-
- P(NMe2)3-Mediated Umpolung Alkylation and Nonylidic Olefination of α-Keto Esters
-
A commercial phosphorus-based reagent (P(NMe2)3) mediates umpolung alkylation of methyl aroylformates with benzylic and allylic bromides, leading to either Barbier-type addition or ylide-free olefination products upon workup. The reaction sequence is initiated by a two-electron redox addition of the tricoordinate phosphorus reagent with an α-keto ester compound (Kukhtin-Ramirez addition). A mechanistic rationale is offered for the chemoselectivity upon which the success of this nonmetal mediated C-C bond forming strategy is based.
- Wang, Sunewang Rixin,Radosevich, Alexander T.
-
supporting information
p. 3810 - 3813
(2015/08/18)
-
- Destruction and Construction: Application of Dearomatization Strategy in Aromatic Carbon-Nitrogen Bond Functionalization
-
The formation of carbon-carbon bonds through the functionalization of aromatic carbon-nitrogen bonds is a highly attractive synthetic strategy in the synthesis of aromatic molecules. In this paper, we report a novel aromatic carbon-nitrogen bond functionalization reaction by using a simple dearomatization strategy. Through this process para-substituted anilines serve as a potential aryl source in the construction of a range of functionalized aromatic molecules, such as quaternary carbon centers, α-keto esters, and aldehydes.
- Wang, Shuo-En,Wang, Linfei,He, Qiuqin,Fan, Renhua
-
p. 13655 - 13658
(2015/11/11)
-
- 2-Oxo promoted hydrophosphonylation & aerobic intramolecular nucleophilic displacement reaction
-
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
-
supporting information
p. 8637 - 8641
(2015/08/24)
-
- First Iridium-Catalyzed Highly Enantioselective Hydrogenation of β-Nitroacrylates
-
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
-
p. 3782 - 3785
(2015/08/18)
-
- Highly chemo-, enantio-, and regioselective synthesis of α,α-disubstituted furanones by Cu-catalyzed conjugate addition
-
A highly chemo-, enantio-, and regioselective synthesis of furanones bearing an α,α-disubstituted quaternary stereogenic center is reported. The Cu-catalyzed enantioselective conjugate addition of organoaluminum reagents to unsaturated ketoesters at room temperature and subsequent lactonization took place. Synthetic transformations of furanones represent facile approaches to various cyclic or acyclic compounds bearing a quaternary stereogenic center. Selective chemistry: A highly chemo-, enantio-, and regioselective synthesis of furanones bearing an α,α-disubstituted quaternary stereogenic center is reported (see scheme). Cu-catalyzed enantioselective conjugate addition of organoaluminum reagents to unsaturated ketoesters at room temperature and subsequent lactonization took place.
- Endo, Kohei,Yakeishi, Sayuri,Takayama, Ryotaro,Shibata, Takanori
-
supporting information
p. 8893 - 8897
(2014/07/22)
-
- Metal-free tandem oxidative aryl migration and C-C bond cleavage: Synthesis of α-ketoamides and esters from acrylic derivatives
-
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
-
supporting information
p. 5772 - 5775
(2015/02/19)
-
- Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
-
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
-
supporting information
p. 15987 - 15990
(2015/02/19)
-
- Electrochemical synthesis of the aryl α-ketoesters from acetophenones mediated by Ki
-
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
-
supporting information
p. 17711 - 17714
(2014/01/17)
-
- An efficient and practical synthesis of aryl and hetaryl α-keto esters
-
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
-
supporting information; experimental part
p. 283 - 289
(2012/03/26)
-
- Chiral cobalt-catalyzed enantioselective aerobic oxidation of α-hydroxy esters
-
A chiral cobalt-catalyzed enantioselective aerobic oxidative kinetic resolution of (±)-α-hydroxy esters, using molecular oxygen as a sole oxidant, is reported and a maximum of selectivity factor (s) 31.9 was achieved with >99% enantiomeric excess for unreacted α-hydroxy esters.
- Alamsetti, Santosh Kumar,Sekar, Govindasamy
-
supporting information; experimental part
p. 7235 - 7237
(2010/12/24)
-
- A rapid and green approach to chiral α-hydroxy esters: asymmetric transfer hydrogenation (ATH) of α-keto esters in water by use of surfactants
-
A series of α-hydroxy esters were rapidly prepared (1.5 h) from α-keto esters via asymmetric transfer hydrogenation (ATH) in water by the use of surfactants for the first time. This green method, catalyzed by a water-soluble and recyclable Ru(II) complex, gave moderate to high enantioselectivities (up to 99.7% ee) with DTAB as an additive and HCOONa as the hydrogen source.
- Yin, Lu,Jia, Xian,Li, Xingshu,Chan, Albert S.C.
-
experimental part
p. 2033 - 2037
(2010/01/16)
-
- One-pot efficient synthesis of aryl α-keto esters from aryl-ketones
-
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
-
experimental part
p. 9797 - 9800
(2010/02/27)
-
- Asymmetrie aerobic oxidation of α-hydroxy acid derivatives by C 4-symmetric, vanadate-centered, tetrakisvanadyl(V) clusters derived from N-salicylidene-α-aminocarboxylates
-
(Chemical Equation Presented) A series of chiral vanadyl(V) methoxides bearing 3-t-butyl-5-substituted N-salicylene-L-valinate and L-t-leucinate as chiral auxiliaries has been prepared. In all cases except the 3,5-di-t-butyl analogue, they exist as monomers both in solution and in the single crystal state. In the case of the 3,5-di-t-butyl analogue, the architectural nature of the vanadyl(V) complex highly depends on the base used during the complex formation event. A pentanuclear C4-symmetric complex was formed when potassium salts were employed instead of the corresponding sodium salts. A central vanadate(V) unit serves to grip four identical chiral monomelic vanadyl(V) units together, by which a potassium ion sits on top of the four flanking units through carbonyl coordinations and serves to hold the whole cluster by cooperation with the central vanadate(V) unit. In comparison with the corresponding monomelic vanadyl(V) methoxide complex, the cluster complex was utilized to facilitate the asymmetric aerobic oxidations of various racemic α-hydroxyesters, -amides, and -thioesters with excellent selectivity factors (krel 40 to >500).
- Chen, Chien-Tien,Bettigeri, Sampada,Weng, Shiue-Shien,Pawar, Vijay D.,Lin, Ya-Hui,Liu, Cheng-Yuan,Lee, Way-Zen
-
p. 8175 - 8185
(2008/02/13)
-
- OPHTHALMIC COMPOSITIONS FOR TREATING OCULAR HYPERTENSION
-
This invention relates to the use of potent potassium channel blockers or a formulation thereof in the treatment of glaucoma and other conditions which leads to elevated intraoccular pressure in the eye of a patient. This invention also relates to the use of such compounds to provide a neuroprotective effect to the eye of mammalian species, particularly humans.
- -
-
Page/Page column 43-44
(2008/06/13)
-
- Diarylimidoylcyanides, an attractive class of intermediate: Novel synthesis of α-anilino-β-nitroenamines, N, N′- Disubstituted amidines and substituted phenyl glyoxate
-
The first report of the use of diarylimidoyl cyanides for the synthesis of α-anilino-β-nitrostyrenes, benzamides, and glyoxalic esters is presented, and the advantage of this class of intermediate over diarylimidoyl chlorides is discussed. Copyright Taylor & Francis Group, LLC.
- Roychowdhury, Abhijit,Kumar, Versha V.,Bhaduri
-
p. 715 - 727
(2007/10/03)
-
- Oxime amides and hydrazone amides having fungicidal activity
-
The invention relates to compounds having usefulness in the control of Take-All disease in plants, particularly cereals, a method for the control of Take-All disease, and fungicidal compositions for carrying out the method. Compounds of the invention are oximes or hydrazones of arylgloxamides or heteroarylglyoxamides or cycloalkenylglyoxamides.
- -
-
Page column 10-11
(2008/06/13)
-
- New approach to biomimetic transamination using bifunctional [1,3]-proton transfer catalysis in thioxanthenyl dioxide imines
-
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
-
p. 3585 - 3594
(2007/10/03)
-
- Oxime amides and hydrazone amides having fungicidal activity
-
The invention relates to compounds having usefulness in the control of Take-All disease in plants, particularly cereals, a method for the control of Take-All disease, and fungicidal compositions for carrying out the method. Compounds of the invention are oximes or hydrazones of arylgloxamides or heteroarylglyoxamides or cycloalkenylglyoxamides.
- -
-
-
- A general and straightforward approach to α,ω-ketoesters
-
Chemoselective cross-coupling reactions of monoesters of dicarboxylic acid chlorides with organocopper reagents derived from Grignard reagents, cuprous bromide, and lithium bromide, provide a simple and straightforward method for synthesizing a variety of ketoesters.
- Babudri, Francesco,Fiandanese, Vito,Marchese, Giuseppe,Punzi, Angela
-
p. 13513 - 13520
(2007/10/03)
-
- Facile Synthesis of α-Keto Carbonyl Compounds by Indirect Anodic Oxidation
-
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
-
p. 1017 - 1020
(2007/10/02)
-
- Pyrylium Salt Sensitized Photochemical Deprotections of Dithioacetals and Ketals
-
Photoreactions of various dithioacetals and ketals using tris(p-chlorophenyl)pyrylium perchlorate as a sensitizer were studied.Irradiation (λ>360 nm) of dichloromethane solutions containing dithioacetals or ketals and pyrylium salt afforded the corresponding carbonyl compounds in good to excellent yields in the presence of molecular oxygen.
- Kamata, Masaki,Murakami, Yukiko,Tamagawa, Yasuko,Kato, Mitsuaki,Hasegawa, Eietsu
-
p. 12821 - 12828
(2007/10/02)
-
- Vanadium-catalysed Novel Oxidation of Arylacetic Esters for the Synthesis of Arylglyoxylic Esters
-
Direct synthesis of arylglyoxylic esters in excellent yields from inexpensive arylacetic esters is realised for the first time by the oxidation of activated methylene using vanadium pillared clay as the catalyst and tert-butylhydroperoxide as an oxidant.
- Choudary, B. M.,Reddy, G. Vidya Sagar,Rao, K. Koteswara
-
p. 323 - 324
(2007/10/02)
-
- Deprotection of 1,3-dithianes by antimony pentachloride via single electron transfer processes
-
A variety of 1,3-dithianes was converted to the corresponding carbonyl compounds in good yields when those substances were treated with antimony pentachloride in methylene chloride. Single electron transfer from dithianes to antimony pentachloride was proposed as an initiation step of the reaction.
- Kamata,Otogawa,Hasegawa
-
p. 7421 - 7424
(2007/10/02)
-
- Kinetics of Pb(IV) Oxidation of Substituted Methyl Mandelates - A L.F.E.R. Study
-
Lead tetra acetate (Pb(IV) or LTA) oxidation of the esters X-C6H4-CH(OH)-COOCH3 (X = H, m-NO2, p-NO2, m-Cl, p-Cl, p-Br, p-CH3 and p-C2H5) gives corresponding keto esters.The reaction is first order in and second order in , and is catalysed by pyridine and 2,6-lutidine.The pyridine catalysed reaction is first order each in , and .A kinetic isotope effect is observed in oxidation of methyl mandelate for both uncatalysed reaction (kH/kD = 4.2) and pyridine catalysed reaction (kH/kD = 1.8).Activation parameters for both uncatalysed and pyridine catalysed reactions are evaluated.The results are in accord with Linear Free Energy Relationship (L.F.E.R.) and the reaction constant (ρ = +0.75) obtained supports proton transfer in the α-C-H bond rupture in the rate limiting step.The role of pyridine in catalysis, as a ligand or as a base is discussed. - Keywords: Kinetics of Pb(IV), Substituted Methyl Mandelates
- Banerjee, Sudheer K.,Shanker, R.,Sachdeva, Om P.
-
p. 467 - 472
(2007/10/02)
-
- Solvent Effect on Kinetics of Oxidation of Methyl Esters of Substituted Mandelic Acids by Lead Tetra Acetate
-
Lead-tetra-acetate (LTA) oxidation of the esters X-C6H4CH(OH)-COOCH3 (X= H, p-Cl, p-CH3* and m-NO2) gives corresponding keto-esters estimated as their 2 : 4 DNP derivatives.Stoichiometry establishes 1 : 1 molar reaction.Increasing the percent AcOH from 1percent to 10percent (v/v) in benzene - AcOH medium retards the reaction sharply along with steepfall in ΔH* and ΔS* and change in * dependence from second order to first order.On further increasing the percent AcOH up to 80percent, the retardation in rate becomes much more gradual and the activation parameters also do not vary significantly.Consistent with the change in activation parameters along with solvent composition, and the fact that methyl mandelate exhibits primary kinetic isotope effect (kH/kD = 4.2) in benzene containing 1percent AcOH, a polar transition state with the possibility of the change from α-C-C bond rupture to α-C-H bond rupture is discussed.
- Banerjee, S. K.,Shanker, R.,Sachdeva, OM P.
-
p. 931 - 936
(2007/10/02)
-
- Palladium(II) Complex-catalysed Formation of α-Keto Acids via Double Carbonylation of Organic Halides
-
Organic halides are doubly carbonylated in the presence of water using the PdCl2(PPh3)2 catalyst leading to the formation of α-keto acids.
- Tanaka, Masato,Kobayashi, Toshi-aki,Sakakura, Toshiyasu
-
p. 837 - 838
(2007/10/02)
-
- Syntheses of Aryl Glyoxylate. I. The Reaction of Alkyl Dichloro(alkoxy)acetates with Aromatics in the Presence of Lewis Acid
-
Ethyl dichloro(ethoxy)acetate(1) and methyl dichloro(methoxy)acetate(2) were characterized.The reaction of 1 and 2 with aromatics in the presence of AlCl3 gave a considerable yield of aromatic α-keto ester.The aromatics included mono- and polymethylbenzene and anisol.The reaction was studied under various conditions and the results were compared with the acylation by ethoxalyl or methoxalyl chloride.The reaction mechanism was also discussed.
- Itoh, Osamu,Nagata, Takayoshi,Nomura, Isamu,Takanaga, Tetsuya,Sugita, Toshio,Ichikawa, Katsuhiko
-
p. 810 - 814
(2007/10/02)
-