cas 5524-56-1, ETHYL 4-METHYLBENZOYLFORMATE

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Electrochemical two-electron oxygen reduction reaction (ORR) induced aerobic oxidation of α-diazoesters
Electrochemical oxygen reduction reaction (ORR) is a powerful tool for introducing oxygen functional groups in synthetic chemistry. However, compared with the well-developed one-electron oxygen reduction process, the applications of two-electron oxygen re
Chen, Liang,Gao, Meng,Lu, Cuifen,Ma, Chao,Ruan, Mengyao,Wen, Ziyang,Yang, Fan,Yang, Guichun
p. 2168 - 2171
(2022/02/17)

Stereoselective Synthesis of Dihydrocoumarins via [1,2]-Phospha-Brook Rearrangement in Three-Component Coupling Reaction of α-Ketoesters, o-Quinone Methides, and Dialkyl Phosphites
A highly regio- and diastereoselective approach for the synthesis of phosphate substituted dihydrocoumarins via Br?nsted base catalyzed [1,2]-phospha-Brook rearrangement is reported. The two-step, one-pot Michael addition of α-phosphonyloxy enolates proceeds by coupling of dialkyl phosphite and α-ketoesters to o-quinone methides, followed by an intramolecular cyclization, providing 3,4-dihydrocoumarin frameworks.
Kaur, Ravneet,Singh, Dipak,Singh, Ravi P.
p. 15702 - 15711
(2021/11/01)

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)

Chemo- And diastereoselective synthesis of pyrrolidines from aroylformates and δ-tosylamino enones via P(NMe2)3-mediated reductive amination/base-catalyzed michael addition cascade
A novel P(NMe2)3-mediated tandem (1 + 4) annulation between aroylformates and δ-tosylamino enones has been developed that affords a facile synthesis of functionalized pyrrolidines in moderate to excellent yields with exclusive chemoselectivity and high diastereoselectivity. Mechanistic investigation reveals that the reaction proceeds through an unprecedented P(NMe2)3-mediated reductive amination/base-catalyzed Michael addition cascade. The reaction herein also represents the first study of the reactivity patterns of the Kukhtin-Ramirez adducts toward ambiphilic nucleophile-electrophiles.
Liu, Rongfang,Liu, Jialin,Cao, Jilei,Li, Ruifeng,Zhou, Rong,Qiao, Yan,Gao, Wen-Chao
supporting information
p. 6922 - 6926
(2020/09/15)

A short route to access oxaspiro[: N,3,3]propellanes
Novel access to oxaspiro[n,3,3]propellanes has been developed from bicyclic lactones directly prepared by a photochemical hydroxymethylation or alternatively by a three-step sequence. Thanks to the presence of additional hydroxy- and propargylic groups, a second cyclization catalyzed by silver or bismuth salts, led to the propellane structure which was finally transformed into spiranic derivatives by a Simmons-Smith reaction or condensation with α-ketoesters.
Nassar, Youssef,Piva, Olivier
supporting information
p. 5811 - 5815
(2020/08/21)

Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
supporting information

(2020/07/15)

Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters
A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also provides an alkoxy moiety for the reaction, which involves the cleavage and reconstruction of C-O bonds.
Luo, Xianglin,He, Runfa,Liu, Qiang,Gao, Yanping,Li, Jingqing,Chen, Xiuwen,Zhu, Zhongzhi,Huang, Yubing,Li, Yibiao
p. 5220 - 5230
(2020/05/18)

Green preparation method of aryl [alpha]-keto ester compound
The invention discloses a green preparation method of an aryl [alpha]-keto ester compound. The method comprises the specific steps that an [alpha]-diazo compound serves as a reaction raw material, copper sulfate serves as a catalyst, water serves as a solvent, a target product aryl [alpha]-keto ester compound is prepared through a reaction at the temperature of 60 DEG C, the structural general formula of the [alpha]-diazo compound is shown in the specification, and the structural general formula of the correspondingly prepared target product aryl [alpha]-keto ester compound is shown in the specification. The method for synthesizing the target product aryl [alpha]-keto ester compound by catalyzing the [alpha]-diazo compound derivative with copper sulfate has the advantages that the reactioncondition is green and mild, the catalyst is cheap and easy to obtain, the operation is simple and convenient, the yield is relatively high, the universality of a reaction substrate is wide, and thelike.
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Paragraph 0053-0056

(2020/05/30)

General Synthesis of Chiral α,α-Diaryl Carboxamides by Enantioselective Palladium-Catalyzed Cross-Coupling
A general synthesis of chiral α,α-diaryl carboxamides is developed by enantioselective cross-coupling between 2-bromo-2-aryl carboxamides and arylboronic acids, leading to a series of chiral α,α-diaryl carboxamides with various electronic properties and functionalities in moderate to excellent enantioselectivities and yields. The employment of a sterically bulky chiral P,P═O ligand L2 is critical for the reactivity and selectivity. This protocol is applied to an efficient asymmetric synthesis of a key intermediate of dopamine receptor agonist SKF 38393.
Li, Bowen,Aliyu, Muinat A.,Gao, Zhenhua,Li, Tiejun,Dong, Wei,Li, Junchen,Shi, Enxue,Tang, Wenjun
supporting information
p. 4974 - 4978
(2020/07/03)

Exploiting Cofactor Versatility to Convert a FAD-Dependent Baeyer–Villiger Monooxygenase into a Ketoreductase
Cyclohexanone monooxygenases (CHMOs) show very high catalytic specificity for natural Baeyer–Villiger (BV) reactions and promiscuous reduction reactions have not been reported to date. Wild-type CHMO from Acinetobacter sp. NCIMB 9871 was found to possess an innate, promiscuous ability to reduce an aromatic α-keto ester, but with poor yield and stereoselectivity. Structure-guided, site-directed mutagenesis drastically improved the catalytic carbonyl-reduction activity (yield up to 99 %) and stereoselectivity (ee up to 99 %), thereby converting this CHMO into a ketoreductase, which can reduce a range of differently substituted aromatic α-keto esters. The improved, promiscuous reduction activity of the mutant enzyme in comparison to the wild-type enzyme results from a decrease in the distance between the carbonyl moiety of the substrate and the hydrogen atom on N5 of the reduced flavin adenine dinucleotide (FAD) cofactor, as confirmed using docking and molecular dynamics simulations.
Xu, Jian,Peng, Yongzhen,Wang, Zhiguo,Hu, Yujing,Fan, Jiajie,Zheng, He,Lin, Xianfu,Wu, Qi
p. 14499 - 14503
(2019/09/17)

Intermolecular Radical Addition to Ketoacids Enabled by Boron Activation
The intermolecular radical addition to the carbonyl group is difficult due to the facile fragmentation of the resulting alkoxyl radical. To date, the intermolecular radical addition to ketones, a valuable approach to construct quaternary carbon centers, remains a formidable synthetic challenge. Here, we report the first visible-light-induced intermolecular alkyl boronic acid addition to α-ketoacids enabled by the Lewis acid activation. The in situ boron complex formation is confirmed by various spectroscopic measurements and mechanistic probing experiments, which facilitates various alkyl boronic acid addition to the carbonyl group and prevents the cleavage of the newly formed C-C bond. Diversely substituted lactates can be synthesized from readily available alkyl boronic acids and ketoacids at room temperature merely under visible light irradiation, without any additional reagent. This boron activation approach can be extended to alkyl dihydropyridines as radical precursors with external boron reagents for primary, secondary, and tertiary alkyl radical additions. The pharmaceutically useful anticholinergic precursors are easily scaled up in multigrams under metal-free conditions in flow reactors.
Xie, Shasha,Li, Defang,Huang, Hanchu,Zhang, Fuyuan,Chen, Yiyun
supporting information
p. 16237 - 16242
(2019/10/14)

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)

Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
supporting information
p. 16490 - 16494
(2019/11/03)

Ambient and aerobic carbon-carbon bond cleavage toward α-ketoester synthesis by transition-metal-free photocatalysis
The α-oxoesterification of the CC double bond in readily available enaminones enabling efficient synthesis of α-ketoesters is developed. The reactions showing general tolerance to the reactions of primary and secondary alcohols proceed well under air via Rose Bengal (RB)-based photocatalysis. Particularly, this mild synthetic method has been discovered to tolerate various polyhydroxylated substrates such as phenolic alcohol, diols and triols with an excellent selectivity of mono-oxoesterification. What is more noteworthy is that α-ketoester functionalized 16-dehydropregnenolone acetate resulting from the elaboration on a natural product has been obtained practically.
Yu, Qing,Zhang, Yating,Wan, Jie-Ping
supporting information
p. 3436 - 3441
(2019/06/24)

Highly adequate oxidative esterification of α-carbonyl aldehydes with alkyl halides in TBAI/TBHP mediated system
An efficient and viable synthesis of α-ketoesters from alkyl halides and α-carbonyl aldehydes has been reported under metal-free conditions. The present method involves oxidative esterification of α-carbonyl aldehydes with alkyl halide using TBAI as a promoter and TBHP as an oxidant to form α-ketoesters in good to excellent yields with versatile structural diversity. Use of commercially accessible and inexpensive substrates, broad substrate scope and good functional group tolerance are the key features of this protocol.
Bhargude, Pooja L.,Lade, Jatin J.,Patil, Bhausaheb N.,Vadagaonkar, Kamlesh S.,Chaskar, Atul C.
supporting information
p. 1325 - 1333
(2019/04/30)

Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: Synthesis of propargyl alcohols and α-ketoesters
The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere (N2 or O2). A N2 atmosphere favours propargyl alcohols via a direct C-C coupling process, whereas an O2 atmosphere results in the generation of α-ketoesters through the oxidative CC/C-O coupling pathway.
Ni, Ke,Meng, Ling-Guo,Ruan, Hongjie,Wang, Lei
supporting information
p. 8438 - 8441
(2019/07/22)

Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis
The alkynylbenziodoxole derivatives are recently developed alkynylation reagents in organic synthesis, which demonstrate excellent radical alkynylation reactivity in photoredox catalysis reactions. Herein we report the synthesis of alkynylbenziodoxole derivatives with difluoro, monofluoro, monomethoxy, and dimethoxy substitution on the benziodoxole moiety, and investigated their radical alkynylation reactivity for the first time. A series of mechanistic experiments were conducted to study the radical acceptor and oxidative quencher reactivity of alkynylbenziodoxoles, in which unsubstituted alkynylbenziodoxoles played balancing roles in both processes, while electron-rich benziodoxole derivatives demonstrate synthetic advantages in some cases.
Pan, Yue,Jia, Kunfang,Chen, Yali,Chen, Yiyun
supporting information
p. 1215 - 1221
(2018/06/13)

Three-Component Activation/Alkynylation/Cyclocondensation (AACC) Synthesis of Enhanced Emission Solvatochromic 3-Ethynylquinoxalines
2-Substituted 3-ethynylquinoxaline chromophores can be readily synthesized by a consecutive activation–alkynylation–cyclocondensation (AACC) one-pot sequence in a three-component manner. In comparison with the previously published four-component glyoxylation starting from electron-rich π-nucleophiles, the direct activation of (hetero)aryl glyoxylic acids allows the introduction of substituents that cannot be directly accessed by glyoxylation. By introducing N,N-dimethylaniline as a strong donor in the 2-position, the emission solvatochromicity of 3-ethynylquinoxalines can be considerably enhanced to cover the spectral range from blue–green to deep red–orange with a single chromophore in a relatively narrow polarity window. The diversity-oriented nature of the synthetic multicomponent reaction concept enables comprehensive investigations of structure–property relationships by Hammett correlations and Lippert–Mataga analysis, as well as the elucidation of the electronic structure of the emission solvatochromic π-conjugated donor–acceptor systems by DFT and time-dependent DFT calculations with the PBEh1PBE functional for a better reproduction of the dominant charge-transfer character of the longest wavelength absorption band.
Merkt, Franziska K.,H?wedes, Simon P.,Gers-Panther, Charlotte F.,Gruber, Irina,Janiak, Christoph,Müller, Thomas J. J.
p. 8114 - 8125
(2018/04/02)

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)

Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: Controlled oxidation of terminal alkynes to glyoxals
Herein, we report a facile visible light induced copper catalyzed controlled oxidation of terminal CC alkynes to α-keto esters and quinoxalines via formation of phenylglyoxals as stable intermediates, under mild conditions by using molecular O2 as a sustainable oxidant. The current copper catalysed photoredox method is simple, highly functional group compatible with a broad range of electron rich and electron poor aromatic alkynes as well as aliphatic alcohols (1°, 2° and 3° alcohols), providing an efficient route for the preparation of α-keto esters (43 examples), quinoxaline and naphthoquinone with higher yields than those in the literature reported thermal processes. Furthermore, the synthetic utility of the products has been demonstrated in the synthesis of two biologically active molecules, an E. coli DHPS inhibitor and CFTR activator, using the current photoredox process. In addition, we applied this methodology to the one-pot synthesis of a heterocyclic compound (quinoxaline, an FLT3 inhibitor) by trapping the intermediate phenylglyoxal with O-phenylenediamine. The intermediate phenylglyoxal can also be isolated and further reacted with an internal alkyne to form naphthoquinone. This process can be readily scaled up to the gram scale.
Das, Deb Kumar,Kumar Pampana, V. Kishore,Hwang, Kuo Chu
p. 7318 - 7326
(2018/10/15)

Switchable C-H Functionalization of N-Tosyl Acrylamides with Acryloylsilanes
A controllable Rh-catalyzed protocol to access alkylation and alkenylation-annulation of N-tosyl acrylamide with acryloyl silane is reported. In contrast to the directing group or catalyst-dependent divergent sp2 C-H alkylation/alkenylation, the intrinsic property of acryloylsilane allows the switchable reaction manifold, thereby affording either alkylation or annulation products with slight modification of the reaction conditions.
Song, Shengjin,Lu, Ping,Liu, Huan,Cai, Sai-Hu,Feng, Chao,Loh, Teck-Peng
supporting information
p. 2869 - 2872
(2017/06/13)

α-Alkoxycarbonyl-α-hydroxy secondary amides from a carbamoylsilane and α-ketoesters
The addition of N-methoxymethyl-N-organylcarbamoyl(trimethyl)silane to α-ketoesters in anhydrous toluene at 60 °C afforded α-alkoxycarbonyl-α-siloxy amides in high yields (75–96%). The methoxymethyl was used as an amino protecting group and could be easily converted into hydrogen atom by simple acid hydrolysis leading to α-alkoxycarbonyl-α- hydroxy secondary amides.
Li, Weidong,Han, Yuling,Chen, Jianxin
p. 5813 - 5819
(2017/09/05)

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.
supporting information
p. 1765 - 1769
(2017/04/13)

Site-directed Mutagenesis of Key Residues Unveiled a Novel Allosteric Site on Human Adenosine Kinase for Pyrrolobenzoxa(thia)zepinone Non-Nucleoside Inhibitors
Most nucleoside kinases, besides the catalytic domain, feature an allosteric domain which modulates their activity. Generally, non-substrate analogs, interacting with allosteric sites, represent a major opportunity for developing more selective and safer therapeutics. We recently developed a series of non-nucleoside non-competitive inhibitors of human adenosine kinase (hAK), based on a pyrrolobenzoxa(thia)zepinone scaffold. Based on computational analysis, we hypothesized the existence of a novel allosteric site on hAK, topographically distinct from the catalytic site. In this study, we have adopted a multidisciplinary approach including molecular modeling, biochemical studies, and site-directed mutagenesis to validate our hypothesis. Based on a three-dimensional model of interaction between hAK and our molecules, we designed, cloned, and expressed specific, single and double point mutants of hAK (Q74A, Q78A, H107A, K341A, F338A, and Q74A-F338A). Kinetic characterization of recombinant enzymes indicated that these mutations did not affect enzyme functioning; conversely, mutated enzymes are endowed of reduced susceptibility to our non-nucleoside inhibitors, while maintaining comparable affinity for nucleoside inhibitors to the wild-type enzyme. This study represents the first characterization and validation of a novel allosteric site in hAK and may pave the way to the development of novel selective and potent non-nucleoside inhibitors of hAK endowed with therapeutic potential.
Savi, Lida,Brindisi, Margherita,Alfano, Gloria,Butini, Stefania,La Pietra, Valeria,Novellino, Ettore,Marinelli, Luciana,Lossani, Andrea,Focher, Federico,Cavella, Caterina,Campiani, Giuseppe,Gemma, Sandra
p. 112 - 120
(2016/02/03)

Chiral Frustrated Lewis Pairs Catalyzed Highly Enantioselective Hydrosilylations of 1,2-Dicarbonyl Compounds
A highly enantioselective hydrosilylation of 1,2-dicarbonyl compounds was successfully realized for the first time utilizing the combination of tricyclohexylphosphine and chiral alkenylborane derived in situ from diyne as a frustrated Lewis pair catalyst. A variety of optically active α-hydroxy ketones and esters were obtained in 52-98% yields with 86-99% ee's.
Ren, Xiaoyu,Du, Haifeng
supporting information
p. 810 - 813
(2016/02/09)

Copper(II)-Catalyzed Benzylic C(sp3)-H Aerobic Oxidation of (Hetero)Aryl Acetimidates: Synthesis of Aryl-α-ketoesters
A straightforward method is developed in this paper for the synthesis of α-ketoesters through copper-catalyzed aerobic oxidation of (hetero)aryl acetimidates using molecular oxygen as a sustainable oxidant. The reaction represents the first example of the direct synthesis of aryl-α-ketoesters from arylacetimidates through the aerobic oxidation of a benzylic C(sp3)-H (CO) bond in moderate to good yield. This transformation occurs under mild reaction conditions with a wide range of substrates and utilizes a readily available oxidant and catalyst. The synthetic utility of this transformation is demonstrated through scaled-up synthesis. A plausible reaction mechanism is also proposed.
Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
p. 12247 - 12257
(2016/12/23)

Novel Synthesis of α-Keto Esters and Amides by an sp3 C-H Oxidation of Nitromethyl Aryl Ketones Promoted by Ion-Supported (Diacetoxyiodo)benzene
A simple and efficient method is described for the preparation of α-keto esters or amides from nitromethyl aryl ketones. In the presence of nucleophiles (alcohols or amines), the ion-supported (di-acetoxyiodo)benzene-promoted sp3 C-H oxidation of nitromethyl aryl ketones proceeded efficiently under mild conditions to give the corresponding α-keto esters and amides in moderate to good yields. This is the first reported use of (diacetoxyiodo)benzene in the synthesis of α-keto esters and amides. The reaction is ecofriendly and has the -advantages of mild conditions, short reaction times, and a recyclable reagent.
Jiang, Xiaoying,Gan, Bing,Liu, Jiwei,Xie, Yuanyuan
supporting information
p. 2737 - 2741
(2016/11/25)

Iron-catalyzed aerobic oxidative cleavage of the C-C σ-bond using air as the oxidant: Chemoselective synthesis of carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds
A simple iron-catalyzed aerobic oxidative C-C σ-bond cleavage of ketones has been developed. Readily available and environmentally benign air is used as the oxidant. This reaction avoids the use of noble metal catalysts or specialized oxidants, chemoselectively yielding carbon chain-shortened aldehydes, ketones and 1,2-dicarbonyl compounds without overoxidation.
Xing, Qi,Lv, Hui,Xia, Chungu,Li, Fuwei
p. 489 - 492
(2016/01/12)

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)

Rhodium(iii)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates
Rhodium-catalyzed C-H allylation of acrylamides with allyl acetates is reported. The use of weakly coordinating directing group resulted in high reaction efficiency, broad functionality tolerance and excellent γ-selectivity, which opens a new synthetic pathway for the access of 1,4-diene skeletons.
Feng, Chao,Feng, Daming,Loh, Teck-Peng
supporting information
p. 342 - 345
(2015/01/09)

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)

A novel method for synthesis of α-keto esters with phenyliodine(III) diacetate
A rapid and efficient synthesis of α-keto esters from β-ketonitriles using phenyliodine(III) diacetate is reported. This protocol gave α-keto esters in good yields. This is the first time to report the application of hypervalent iodine(III) reagents in the synthesis of α-keto esters. A plausible reaction mechanism is proposed.
Xie, Yuanyuan,Liu, Jiwei,Huang, Yingyi,Yao, Lixia
supporting information
p. 3793 - 3795
(2015/06/08)

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)

Design, synthesis, acaricidal activity, and mechanism of oxazoline derivatives containing an oxime ether moiety
Two series of novel 2,4-diphenyl-1,3-oxazolines containing an oxime ether moiety were designed and synthesized via the key intermediate N-(2-chloro-1-(p-tolyl)ethyl)-2,6-difluorobenzamide. The bioassay results showed that the target compounds with an oxime ether substituent at the para position of 4-phenyl exhibited excellent acaricidal activity against Tetranychus cinnabarinus in the laboratory. Moreover, all of the target compounds had much higher activities than etoxazole, as the ovicidal and larvicidal activities of the target compounds I-a-I-l and II-a-II-n against T. cinnabarinus were all over 90% at 0.001 mg L-1, but etoxazole gave only 30% and 40% respectively at the same concentration. The activity order of compounds with regard to acaricidal activity in vivo was almost consistent with their affinity activity with sulfonylurea receptor (SUR) of Blattella germanica in vitro, hence, it was supposed that the acaricidal mechanism of action of the target compounds was that they can bind with the site of SUR and therefore inhibit chitin synthesis. Moreover, the eminent effect of the compound II-l, [2-(trifluoromethyl)benzaldehyde O-(4-(2-(2,6-difluorophenyl)-4,5-dihydrooxazol- 4-yl)benzyl) oxime], against Panonychus citri and T. cinnabarinus in the field indicated that II-l exhibited a promising application prospect as a new candicate for controlling spider mites in the field.
Li, Yongqiang,Li, Chaojie,Zheng, Yanlong,Wei, Xingcun,Ma, Qiaoqiao,Wei, Peng,Liu, Yuxiu,Qin, Yaoguo,Yang, Na,Sun, Yufeng,Ling, Yun,Yang, Xinling,Wang, Qingmin
p. 3064 - 3072
(2014/05/06)

Design, synthesis, acaricidal activity, and mechanism of oxazoline derivatives containing an oxime ether moiety
Two series of novel 2,4-diphenyl-1,3-oxazolines containing an oxime ether moiety were designed and synthesized via the key intermediate N-(2-chloro-1-(p-tolyl)ethyl)-2,6-difluorobenzamide. The bioassay results showed that the target compounds with an oxime ether substituent at the para position of 4-phenyl exhibited excellent acaricidal activity against Tetranychus cinnabarinus in the laboratory. Moreover, all of the target compounds had much higher activities than etoxazole, as the ovicidal and larvicidal activities of the target compounds I-a-I-l and II-a-II-n against T. cinnabarinus were all over 90% at 0.001 mg L-1, but etoxazole gave only 30% and 40% respectively at the same concentration. The activity order of compounds with regard to acaricidal activity in vivo was almost consistent with their affinity activity with sulfonylurea receptor (SUR) of Blattella germanica in vitro, hence, it was supposed that the acaricidal mechanism of action of the target compounds was that they can bind with the site of SUR and therefore inhibit chitin synthesis. Moreover, the eminent effect of the compound II-l, [2-(trifluoromethyl)benzaldehyde O-(4-(2-(2,6-difluorophenyl)-4,5-dihydrooxazol-4-yl)benzyl) oxime], against Panonychus citri and T. cinnabarinus in the field indicated that II-l exhibited a promising application prospect as a new candicate for controlling spider mites in the field.
Li, Yongqiang,Li, Chaojie,Zheng, Yanlong,Wei, Xingcun,Ma, Qiaoqiao,Wei, Peng,Liu, Yuxiu,Qin, Yaoguo,Yang, Na,Sun, Yufeng,Ling, Yun,Yang, Xinling,Wang, Qingmin
p. 3064 - 3072
(2015/04/22)

Synthesis, biological evaluation, and docking analysis of a novel family of 1-methyl-1H-pyrrole-2,5-diones as highly potent and selective cyclooxygenase-2 (COX-2) inhibitors
As a continuous research for discovery of new COX-2 inhibitors, we present the simple chemical synthesis, in vitro biological screening, and molecular docking study of 1H-pyrrole-2,5-dione derivatives. New synthetic compounds were evaluated for the inhibitory activities on LPS-induced PGE2 production in RAW 264.7 macrophage cells as well as the COX-1 and COX-2 inhibitory potency. Among them, compound 9d (MPO-0029) was identified as more potent and selective COX-2 inhibitor [PGE2 IC50 = 8.7 nM, COX-2 IC50 = 6.0 nM; COX-2 selectivity index (SI) = >168] than celecoxib. Molecular docking experiments were further performed against COX-2 and COX-1 isozymes to determine their probable binding models. Results of molecular docking studies revealed that compound 9d (MPO-0029) has stronger binding interaction with COX-2 than with COX-1 isozyme, and provided successfully complementary theoretical support for the obtained experimental biological data.
Kim, Kyung Ju,Choi, Min Ji,Shin, Ji-Sun,Kim, Minju,Choi, Hye-Eun,Kang, Seoung Mook,Jin, Jae Ho,Lee, Kyung-Tae,Lee, Jae Yeol
p. 1958 - 1962
(2014/04/17)

MICROCAPSULES CONTAINING A GAS-GENERATING PHOTOLABILE KETOACID OR KETOESTER AND USES THEREOF
The present invention relates to water-dispersable microcapsules comprising an oil phase, e.g. a perfume, containing a photolabile α-ketoacid or α-ketoester capable of generating a gas upon exposure to light. The gas is able to cause an extension or the breaking of the microcapsule allowing the release of the oil phase and thus increasing the long-lastingness of the odor perception. The present invention concerns also the use of said microcapsules in perfumery as well as the perfuming compositions or perfumed articles comprising the invention's microcapsules to provide a prolonged release of fragrant molecules.
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Page/Page column 23; 24

(2014/12/12)

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)

Rhodium-catalyzed intermolecular reaction of alkyl azides with diazo(aryl)acetates
An efficient intermolecular interception of alkyl azides by diazo(aryl)acetates was achieved in the presence of dirhodium tetraoctanoate. The initial products were unstable α-imino esters, and overaddition of carbenoids to the C-N double bonds was avoided. After acidic workup, the corresponding α-keto esters were obtained in good to excellent yields. Georg Thieme Verlag Stuttgart New York.
Gu, Peiming,Wu, Xiu-Ping,Su, Yan,Li, Xue-Qiang,Xue, Ping,Li, Rui
supporting information
p. 535 - 538
(2014/03/21)

A stereoselective route to 6-substituted pyrrolo-1,5-benzoxazepinones and their analogues
We developed a novel and convenient stereoselective path for the preparation of pyrrolo-1,5-benzoxazepinones (PBOs). This innovative route envisaged the employment of (-)-menthol as convenient chiral auxiliary and a key SNAr for the stereoselective preparation of a tertiary aryl-alkyl ether. As a further advancement, we exploited this newly conceived synthetic route for the preparation of 2-substituted PBO analogues to either undergo biological evaluation themselves or give access to a variety of further functionalization options.
Brindisi, Margherita,Gemma, Sandra,Alfano, Gloria,Kshirsagar, Giridhar,Novellino, Ettore,Campiani, Giuseppe,Butini, Stefania
p. 5387 - 5390
(2013/09/12)

Direct asymmetric aldol addition-isomerization of α,β- unsaturated γ-butyrolactam with aryl α-ketoesters: Synthesis of MBH-type products
A highly efficient direct asymmetric aldol addition-isomerization reaction at the α-position of α,β-unsaturated γ-butyrolactam and aryl α-ketoesters by using a bifunctional thiourea catalyst was achieved. Morita-Baylis-Hillman type adducts containing a quaternary stereocenter can be obtained in high yields and with excellent enantioselectivities (up to 99% ee). The Royal Society of Chemistry 2013.
Zhang, Jinlong,Liu, Xihong,Ma, Xiaojuan,Wang, Rui
supporting information
p. 3300 - 3302
(2013/06/04)

Directing-group-assisted copper-catalyzed olefinic trifluoromethylation of electron-deficient alkenes
Assistance provided: The directing group in the title reaction not only activates the substrates but also allows the stereospecific formation of cis-trifluoromethylated products. The reaction is operationally simple and tolerates a wide variety of functional groups, thus providing an efficient method for the stereoselective synthesis of β-CF3-functionalized acrylamide derivatives. Copyright
Feng, Chao,Loh, Teck-Peng
supporting information
p. 122414 - 122417
(2013/12/04)

Synthesis, characterization and antiinflammatory activity of novel pyrazolyl ketoamides
Compounds containing pyrazolylurea group are known to possess potent anti-inflammatory activity by inhibiting cell signalling system. One of the potent compounds has demonstrated CNS related adverse effects in human studies which has further intensified the quest to search potent but safe antiinflammatory agents. In the present study, an attempt has been made to modify the urea group into α-ketoamide group. The synthesis involved the coupling of 5-aminopyrazole with substituted α-keto acids in presence of a coupling agent to afford the desired compounds and the structures of the synthesized compounds have been confirmed by spectral data. Compounds have been screened for antiinflammatory activity by carrageenan induced rat paw method. Compounds 6c, 6e and 6f demonstrate greater than 70% paw oedema protection when compared with indomethacin. The preliminary structure activity relationship suggests that the electron withdrawing groups are essential for potent antiinflammatory activity of compounds.
Mahaveer,Kulkarni,Radakrishna,Chandrashekar,Achaiah
p. 818 - 823
(2013/07/26)

2-Aryl-2-nitroacetates as central precursors to aryl nitromethanes, α-ketoesters, and α-amino acids
Nitroarylacetates are useful small molecular building blocks that act as precursors to α-ketoesters and aryl nitromethanes as well as α-amino acids. Methods were developed that produce each of these compound types in good yields. Two different conditions
Metz, Alison E.,Kozlowski, Marisa C.
p. 717 - 722
(2013/02/25)

Highly homogeneous stereocontrolled construction of quaternary hydroxyesters by addition of dimethylzinc to α-ketoesters promoted by chiral perhydrobenzoxazines and B(OEt)3
A highly efficient enantioselective addition of Me2Zn to α-ketoesters, assisted by a chiral perhydro-1,3-benzoxazine ligand, is described. This novel catalytic system offers homogeneous elevated enantioselectivities in the preparation of α-hydroxyesters that bear a quaternary stereocenter, with a minor dependence on electronic and steric effects when aromatic, heteroaromatic, or aliphatic α-ketoesters are employed. The catalyst can be recovered and reused without loss of activity.
Infante, Rebeca,Nieto, Javier,Andres, Celia
supporting information; experimental part
p. 4375 - 4379
(2012/05/20)

Aryllithiums with increasing steric crowding and lipophilicity prepared from chlorides in diethyl ether. the first directly prepared room-temperature-stable dilithioarenes
A convenient procedure has been developed for the preparation of synthetically useful, room-temperature-stable aryllithiums starting from aryl chlorides and lithium metal. The method provides a route to aryllithiums which have previously not been accessible cleanly or could only be prepared by using more expensive starting materials.
Screttas, Constantinos G.,Steele, Barry R.,Micha-Screttas, Maria,Heropoulos, Georgios A.
supporting information
p. 5680 - 5683
(2013/01/15)

Catalytic enantioselective protonation of α-oxygenated ester enolates prepared through phospha-brook rearrangement
(Chemical Equation Presented) Phosphonates go chiral: The organocatalytic enantioselective reaction of α-ketoesters with phosphites using cinchona alkaloids and Na2CO3 has afforded α-phosphonyloxy esters with high enantioselectivities (see scheme). This process allows the formation of both enantiomers of the product. A catalyst loading of as low as 2 mol% does not result in a significant decrease of the enantioselectivity.
Hayashi, Masashi,Nakamura, Shuichi
supporting information; experimental part
p. 2249 - 2252
(2011/04/16)

Enantioselective enolate protonation in sulfamichael addition to r-substituted n-acryloyloxazolidin-2-ones with bifunctional organocatalyst
Organocatalytic conjugate addition of thiols to R-substituted N-acryloyloxazolidin-2-ones followed by asymmetric protonation has been studied in the presence of cinchona alkaloid derived thioureas. Both of the enantiomers are accessible with the same level of enantioselectivity using pseudoenantiomeric quinine/quinidine derived catalysts. The addition/protonation products have been converted to useful biologically active molecules. 2011 American Chemical Society.
Rana, Nirmal K.,Singh, Vinod K.
supporting information; experimental part
p. 6520 - 6523
(2012/02/01)

Construction of 1,2,5-tricarbonyl compounds using methyl cyanoacetate as a glyoxylate anion synthon combined with copper(I) iodide-catalyzed aerobic oxidation
A practical and efficient synthesis of various 1,2,5-tricarbonyl compounds is described. The synthesis has been carried out by a conjugate addition of methyl cyanoacetate to the β-position of α,β-unsaturated carbonyl compounds and a subsequent copper(I) iodide-catalyzed aerobic oxidation. In addition, various α-aryl- and α-alkyl-α-keto esters have been synthesized using a similar approach. Copyright
Kim, Se Hee,Kim, Ko Hoon,Kim, Jae Nyoung
supporting information; experimental part
p. 3335 - 3339
(2012/01/19)

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)