- A Novel Synthesis of 4-Dioxy-2-enones from 1,3-Dienes using Pyridinium Dichromate-tert-Butyl Hydroperoxide
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Treatment of 1,3-dienes with the pyridinium dichromate (PDC)-t-BuOOH reagent system leads directly to the formation of 4-tert-butyldioxy-2-enones in good yield under mild reaction conditions.
- Bhat, Shridhar,Chidambaram, Nallaperumal,Chandrasekaran, Srinivasan
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- Visible-Light-Driven Z -Selective Reaction of Methyl Ketones with DMSO: A Mild Synthetic Approach to Methylthio-Substituted 1,4-Enedione Promoted by Selectfluor
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Here we disclose a simple, visible-light-driven Z -selective synthesis of methylthio-substituted 1,4-enedione in a single step promoted by Selectfluor. Dimethyl sulfoxide is used as both the 'thio' source and the solvent. Molecular iodine and potassium persulfate are used as catalyst and oxidant, respectively. White light (CFL-30W) is used as the light source. The proposed mechanism involves a Kornblum reaction followed by aldol reaction.
- Rastogi, Gaurav K.,Deb, Mohit L.,Baruah, Pranjal K.
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p. 1095 - 1102
(2020/11/02)
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- Stereoselective Synthesis of cis-2-Ene-1,4-diones via Aerobic Oxidation of Substituted Furans Catalyzed by ABNO/HNO3
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We report a highly efficient and selective catalytic system, ABNO (9-azabicyclo-[3.3.1]nonane N-oxyl)/HNO3, for the aerobic oxidation of substituted furans to cis-2-ene-1,4-diones under mild reaction conditions using oxygen as the oxidant. The catalyst system is amenable to various substituted (mon-, di-, and tri-) furans and tolerates diverse functional groups, including cyano, nitro, naphthyl, ketone, ester, heterocycle, and even formyl groups. Based on the control and 18O-labeling experiments, the possible mechanism of the oxidation is proposed.
- Yang, Liqun,Wang, Jingyang,Wang, Yue,Li, Xiaotong,Liu, Wei,Zhang, Zhaoguo,Xie, Xiaomin
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p. 14311 - 14320
(2021/10/25)
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- Aerobic Oxidative Dehydrogenation of Ketones to 1,4-Enediones
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An efficient and unprecedented strategy for the synthesis of 1,4-enediones from saturated ketones has been developed via palladium-catalyzed oxidative dehydrogenation. The protocol employs molecular oxygen as the sole oxidant and represents an atom- and step-economic process. The approach showed broad substrate scope, good functional group tolerance, and complete E-stereoselectivity. The reaction mechanism has been investigated through deuterium-labeling experiments and intermediate experiments.
- Zhao, Bao-Yin,Zhang, Xing-Long,Guo, Rui-Li,Wang, Meng-Yue,Gao, Ya-Ru,Wang, Yong-Qiang
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supporting information
p. 1216 - 1221
(2021/02/20)
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- Diastereoselective sp3-C–H Functionalization of Arylmethyl Ketones and Transformation of E- to Z-Products Through Photocatalysis
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We have developed an efficient metal-free route for the synthesis of 1,4-enedione derivatives under microwave irradiation by reacting easily available arylmethylketones with DMSO or diphenyl sulfoxide in the presence of TBAI and persulfate. The reaction is very clean and completes within very short time. All the reagents and catalysts are cheap and environmentally benign. In addition, the E-isomer of the products can easily be transformed into the Z-isomer by using eosin Y photocatalyst under the irradiation of white CFL.
- Rastogi, Gaurav K.,Deka, Bhaskar,Deb, Mohit L.,Baruah, Pranjal K.
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supporting information
p. 424 - 428
(2019/12/03)
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- Synergistic Catalysis of Se and Cu for the Activation of α-H of Methyl Ketones with Molecular Oxygen/Alcohol to Produce α-Keto Acetals?
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Selenium and copper synergistically catalyzed the oxidation/alkoxylation of methyl ketones to synthesize α-keto acetals directly. Using O2 as oxidant and alcohol as solvent and alkoxylation reagent, the reaction is practical from industrial viewpoint. Mechanistic studies revealed that copper promoted the oxidation of organoselenium intermediates with O2 to allow the key rearrangement and selenoxide syn-elimination regenerating the catalytically active organoselenium species.
- Chen, Chao,Cao, Zhicheng,Zhang, Xu,Li, Yiming,Yu, Lei,Jiang, Xuefeng
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p. 1045 - 1051
(2020/06/30)
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- Proton-Coupled Electron Transfer: Transition-Metal-Free Selective Reduction of Chalcones and Alkynes Using Xanthate/Formic Acid
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Highly chemoselective reduction of α,β-unsaturated ketones to saturated ketones and stereoselective reduction of alkynes to (E)-alkenes has been developed under a transition-metal-free condition using a xanthate/formic acid mixture through proton-coupled electron transfer (PCET). Mechanistic experiments and DFT calculations support the possibility of a concerted proton electron-transfer (CPET) pathway. This Birch-type reduction demonstrates that a small nucleophilic organic molecule can be used as a single electron-transfer (SET) reducing agent with a proper proton source.
- Prasanna, Ramanathan,Guha, Somraj,Sekar, Govindasamy
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supporting information
p. 2650 - 2653
(2019/04/17)
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- Direct Aerobic Oxidative Reactions of 2-Hydroxyacetophenones
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Valuable and direct aerobic oxidation reactions of 2-hydroxyacetophenones were explored. The concept was based on the in situ treatment of small quantities of aerobically formed α-keto aldehydes that drove the reactions to the corresponding products. This new strategy was applied for a variety of oxidative reactions of 2-hydroxyacetophenones, and valuable products such as phthalides, quinoxalines, and α-keto amides were obtained in good to high yields.
- Sahoo, Subas Chandra,Nath, Utpal,Pan, Subhas Chandra
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supporting information
p. 4434 - 4438
(2017/08/23)
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- Ring Opening of π-Delocalized 2,5-Diphenyltellurophene by Chemical or Self-Sensitized Aerobic Photooxidation
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We report the self-sensitized aerobic photooxidation of 2,5-diphenyltellurophene (PT). Irradiation of PT induces rapid intersystem crossing to the triplet excited state, which undergoes energy transfer to oxygen to form singlet oxygen. Reaction of the heterocycle with singlet oxygen was found to occur at the carbon framework through a 1,4-cycloaddition reaction rather than at tellurium to form the Te(IV) telluroxide, as is commonly observed for other tellurium-containing heterocycles. This leads to oxidative ring-opening of the tellurophene to form (Z)-1,4-diphenylbut-2-ene-1,4-dione ((Z)-ED) with extrusion of TeO2. In attempts to study the formation of the Te(IV) telluroxide and Te(VI) tellurone by chemical oxidation with m-chloroperoxybenzoic acid (mCPBA), we discovered that PT undergoes an oxidative ring-opening reaction to the same ene-dione product after reaction with 4 equiv of mCPBA. Extrusion of TeO2 was also observed in this case. This ring-opening reaction was studied in detail by NMR spectroscopy, GC-MS, and density functional theory calculations.
- Carrera, Elisa I.,Seferos, Dwight S.
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p. 2612 - 2621
(2017/07/28)
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- Synthesis of (E)-1,4-diaryl-2-butene-1,4-diones
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We report a facile route for the preparation of symmetric and unsymmetric (E)-1,4-diaryl-2-butene-1,4-diones 3 by a two-step route, including (1) nucleophilic substitution of 1 with sulfinic acid sodium salts, and (2) K2CO3 mediated alkylation of β-ketosulfones 4 with 1 followed by sequential desulfonylation of the resulting 1,4-diketones 5 in acetone. These products were obtained in high yields.
- Chan, Chieh-Kai,Chang, Meng-Yang
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p. 390 - 405
(2017/01/29)
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- Visible-light-mediated oxidative dimerization of arylalkynes in the open air: Stereoselective synthesis of (Z)-1,4-enediones
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An organic photoredox catalytic one-pot protocol is developed for the highly stereoselective synthesis of (Z)-1,4-enediones. The reaction starts directly from alkyne precursors, using 4-(4-cyanophenyl)-2,6-diphenylpyrylium tetrafluoroborate (CN-TPT) as an efficient photosensitizer and dioxygen in the air as a green oxidant. A Csp-Csp oxidative coupling/[4 + 2] cyclization (with dioxygen)/fragmentive isomerization cascade mechanism was proposed. The predominant formation of (Z)-1,4-enediones is attributed to the efficient visible-light illumination from blue LEDs, along with possible energy transfer from the photosensitizer CN-TPT to the E-isomers.
- Wei, Donglei,Liang, Fushun
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supporting information
p. 5860 - 5863
(2016/11/29)
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- Synthesis of Aromatic Retinoids and Curcuminoids and Evaluation of their Antiproliferative, Antiradical, and Anti-inflammatory Activities
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Natural retinoids and curcuminoids are known for their broad spectrum of biological properties, such as antioxidant, anti-inflammatory, antitumor, and so forth. In this work, a convenient synthesis of aromatic retinoids and curcuminoids from vinyl or allyl ketones, and the corresponding alcohols, using olefin metathesis as a key reaction, was elaborated. The best yields and diastereoselectivities were obtained from allylic or homoallylic alcohols by employing the two-step cross-metathesis/oxidation procedure. The synthesized analogues were tested for their antiproliferative activity on human cancer cell lines of various origin (leukemia CEM, adenocarcinoma MCF7, cervical carcinoma HeLa) as well as for their antioxidant and anti-inflammatory activity in vitro. All examined derivatives exhibited strong anti-inflammatory activity in vitro without affecting cell viability. They also showed strong cytotoxicity against leukemia cell line CEM, except for 18 and 35. The antioxidant activity of the tested compounds was rather weak.
- Morzycki, Jacek W.,Rárová, Lucie,Grúz, Ji?i,Sawczuk, Tomasz,Kie?czewska, Urszula,Siergiejczyk, Leszek,Wojtkielewicz, Agnieszka
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p. 339 - 350
(2016/08/19)
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- Synthesis of (E)-1,4-enediones from α-halo ketones through a sodium sulfinate mediated reaction
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We developed a mild and practical protocol for the synthesis of 1,4-enedione from α-halo ketones through a sodium sulfinate mediated reaction. This reaction enables the construction of symmetric and unsymmetric 1,4-enedione with complete E selectivity. Sodium 4-toluenesulfinate plays an important role in this reaction.
- Li, Su-Yi,Wang, Xiao-Bing,Jiang, Neng,Kong, Ling-Yi
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supporting information
p. 8035 - 8039
(2015/02/05)
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- ZnII- and AuI-catalyzed regioselective hydrative oxidations of 3-En-1-ynes with selectfluor: Realization of 1,4-dioxo and 1,4-oxohydroxy functionalizations
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Catalytic 1,4-dioxo functionalizations of 3-en-1-ynes to (Z)- and (E)-2-en-1,4-dicarbonyl compounds are described. This regioselective difunctionalization was achieved in one-pot operation through initial alkyne hydration followed by in situ Selectfluor oxidation. The presence of pyridine alters the reaction chemoselectivity to give 4-hydroxy-2-en-1-carbonyl products instead. A cooperative action of pyridine and ZnII assists the hydrolysis of key oxonium intermediate.
- Jadhav, Appaso Mahadev,Gawade, Sagar Ashok,Vasu, Dhananjayan,Dateer, Ramesh B.,Liu, Rai-Shung
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p. 1813 - 1817
(2014/03/21)
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- Asymmetric diastereoselective synthesis of spirocyclopropane derivatives of oxindole
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A new asymmetric organocatalytic synthesis of spirocyclopropane oxindoles has been developed. The method is based on the Michael addition of N-Boc-protected 3-chlorooxindole to unsaturated 1,4-dicarbonyl compounds, affording trans-substituted spirocyclopropane oxindole derivatives in high diastereo- and enantioselectivity. Copyright
- Oseka, Maksim,Noole, Artur,Zari, Sergei,Oeeren, Mario,Jaerving, Ivar,Lopp, Margus,Kanger, Tonis
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p. 3599 - 3606
(2014/06/23)
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- Enaminones via ruthenium-catalyzed coupling of thioamides and α-diazocarbonyl compounds
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Enaminones can be prepared via the Rh2(OAc)4- catalyzed coupling of α-diazocarbonyl compounds with thioamides. However, rhodium is the most expensive and least abundant among the dominant precious metals used for catalysis. Furthermore, a very limited substrate scope is known for the intermolecular rhodium catalyzed coupling reaction. Therefore, there is a need to find a more economical catalyst substitute with a broad substrate scope. In this paper, we describe the use of Ru(II) catalysts for the synthesis of enaminones. The reaction can be performed efficiently with the Grubbs first-generation catalyst or [(Ph)3P]3RuCl2 in a sealed tube. Both catalysts are much less expensive than Rh 2(OAc)4. Secondary and tertiary thioamides, when reacted with α-diazodiesters, α-diazoketoesters, α-diazodiketones, and α-diazomonoketones give enaminones. Primary thioamides give thiazole derivatives when reacted with α-diazomonoketones. However, with other diazo compounds, primary thioamides also give enaminones. All enaminones are obtained in good yields and with good diastereoselectivity. Accordingly, the method described in this paper is an efficient and economical alternative to the Rh2(OAc)4-catalyzed coupling process.
- Koduri, Naga D.,Wang, Zhiguo,Cannell, Garrett,Cooley, Kate,Lemma, Tsebaot Mesfin,Miao, Kun,Nguyen, Michael,Frohock, Bram,Castaneda, Maria,Scott, Halee,Albinescu, Dragos,Hussaini, Syed R.
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p. 7405 - 7414
(2014/09/17)
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- A highly tunable stereoselective dimerization of methyl ketone: Efficient synthesis of e - And Z-1,4-enediones
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A new method for the tunable synthesis of 1,4-enedione directly from aromatic methyl ketone is described. This tandem reaction enables the construction of symmetric and unsymmetric 1,4-enediones with complete E-selectivity. Moreover, the resulting E-1,4-enedione could be transformed into a Z-isomer by irradiation with 23 W of white light.
- Xu, Kun,Fang, Yang,Yan, Zicong,Zha, Zhenggen,Wang, Zhiyong
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supporting information
p. 2148 - 2151
(2013/06/05)
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- Bulk gold-catalyzed reactions of diazoalkanes with amines and O2 to give enamines
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Bulk gold powder, consisting of approximately 5-50 μm particles, catalyzes reactions of diazoalkanes E(H)C=N2, where E is CO 2Et or PhC(O), with amines R1R2NH and O 2 to give enamine products (R1R2N)(E)C=CH(E) in 58-94% yield. The reactions are proposed to occur by initial formation of surface-bound (E)(H)C: carbene groups that are attacked by nucleophilic amines. The enamine products are very different than those obtained in reactions catalyzed by homogeneous transition metal complexes. These reactions of diazoalkanes, amines, and O2 represent a new type of bulk gold-catalyzed reaction.
- Zhou, Yibo,Angelici, Robert J.,Keith Woo
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scheme or table
p. 8 - 15
(2010/11/24)
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- Indirect regioselective heteroarylation of indoles through a Friedel-Crafts reaction with (E)-1,4-diaryl-2-buten-1,4-diones
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A two-step synthesis of 3-heteroaryl indoles has been developed. The first step of the sequence involves a Friedel-Crafts alkylation of indoles with 1,4-diaryl-2-buten-1,4-diones to give the corresponding indoles bearing a 1,4-dicarbonyl moiety. The reaction is catalyzed by InCl3 and takes place with good yields. Cyclization of the diones under different Paal-Knorr conditions allows to prepare indoles substituted at the C3 position with 3-furanyl, 3-pyrrolyl- and 3-thienyl moieties.
- Blay, Gonzalo,Fernández, Isabel,Monleón, Alicia,Pedro, José R.,Vila, Carlos
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experimental part
p. 9264 - 9270
(2010/01/06)
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- Catalytic reactions of carbene precursors on bulk gold metal
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Bulk gold metal powder, consisting of particles (5-50 μm) much larger than nanoparticles, catalyzes the coupling of carbenes generated from diazoalkanes (R2C=N2) and 3,3-diphenylcyclopropene (DPCP) to form olefins. It also catalyzes cyclopropanation reactions of these carbene precursors with styrenes. The catalytic activity of the gold powder depends on the nature of the gold particles, as determined by TEM and SEM studies. The reactions can be understood in terms of mechanisms that involve the generation of carbene R2C: intermediates adsorbed on the gold surface.
- Zhou, Yibo,Trewyn, Brian G.,Angelici, Robert J.,Woo, L. Keith
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experimental part
p. 11734 - 11743
(2009/12/08)
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- Lewis acid-catalyzed one-pot, three-component route to chiral 3,3′-bipyrroles
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(Chemical Equation Presented) 3,3′-Bipyrroles 3 could be synthesized using a double Michael addition reaction involving diaroyl acetylene 1 and the appropriate 1,3-dicarbonyls 2 using ammonium acetate as a nitrogen source. The axial chirality of bipyrrole was anticipated from the X-ray crystal structure and DFT calculations and confirmed by separating the racemates on a chiral column and subsequent CD spectra of the enantiomers. The absolute configuration of the enantiomers was achieved by theoretical CD spectra calculation using the ZINDO method.
- Dey, Sumit,Pal, Churala,Nandi, Debkumar,Giri, Venkatachalam Sesha,Zaidlewicz, Marek,Krzeminski, Marek,Smentek, Lidia,Hess Jr., B. Andes,Gawronski, Jacek,Kwit, Marcin,Babu, N. Jagadeesh,Nangia, Ashwini,Jaisankar, Parasuraman
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supporting information; experimental part
p. 1373 - 1376
(2009/04/10)
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- Simple, efficient, and stereoselective oxidation of triphenylfurans to cis-but-2-ene-1,4-diones
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Triphenylfurans are stereoselctively oxidized to cis-but-2-ene-1,4-diones, suitable precursors of 3(2H)-furanones, in very good yields using ammonium nitrate or potassium nitrate in 80% aqueous acetic acid. Copyright Taylor & Francis Group, LLC.
- Rappai, John P.,Prathapan, Sreedharan,Unni, Manthitta V. Vishnu,Unnikrishnan, Perupparampil A.
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p. 571 - 574
(2007/10/03)
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- Iron (III) perchlorate adsorbed on silica gel: A reagent for organic functional group transformations
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Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic-grade silica gel in the presence of organic solvents (S=water, acetonitrile, or lower fatty acids) produces a supported reagent, Fe(ClO4)3(S)6/SiO2. This reagent has been found to be effective for the rapid organic functional group transformations such as dimerization of alkynes, aromatic hydrocarbons, selective oxidation of thiols to disulfides, and transannular reactions in 1,5-cyclooctadienes on grinding using pestle and mortar in the solid state. Copyright Taylor & Francis Group, LLC.
- Parmar, Anupama,Kumar, Harish
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p. 2301 - 2308
(2008/02/10)
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- Reductive ring-opening reaction of 2,3-epoxy-1,4-butanediones with SbCl3-Bu4NI in the presence of Na2S 2O3·5H2O
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1,4-Disubstituted 2,3-epoxy-1,4-butanediones were converted to 1,4-disubstituted 2-hydroxy-1,4-butanediones with SbCl3-Bu 4NI in the presence of Na2S2O 3-5H2O. The ring opening of terminal epoxides can also be accomplished to afford the corresponding haloalcohol with SbCl3 and tetrabutylammonium halides, Bu4NX (X = Cl, Br, I) under the same reaction conditions. Copyright Taylor & Francis, Inc.
- Sayama, Shinsei
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p. 2115 - 2124
(2007/10/03)
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- Synthesis and characterization of 2-phenyl-4-benzoyl-6,7-dihydro-5H-cyclopenta[b]pyridine and its derivatives
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Amination-cyclization of triketones derived from variously substituted dibenzoyl ethylene and cyclopentanone furnished 2-phenyl-4-benzoyl-6,7-dihydro-5H-cyclopenta[b]pyridine and its derivatives.
- Rao, H. Surya Prakash,Senthilkumar,Jeyalakshmi
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- A novel oxidative dimerization of acetylenes to conjugated dicarbonyl systems using iron (III) perchlorate
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Acetylenes 1a-e, terminal as well as substituted, have been converted into α,β- unsaturated dicarbonyl systems 2a-e in good to excellent yields when reacted with Iron (III) perchlorate (ITP) using acetonitrile as the solvent.
- Rana,Kaur,Kumar,Kumar,Anand
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p. 1170 - 1171
(2007/10/03)
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- Polymer pyrolysis and oxidation studies in a continuous feed and flow reactor: Cellulose and polystyrene
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A dual-zone, continuous feed tubular reactor is developed to assess the potential for formation of products from incomplete combustion in thermal oxidation of common polymers. Solid polymer (cellulose or polystyrene) is fed continuously into a volatilization oven where it fragments and vaporizes. The gas-phase polymer fragments flow directly into a second, main flow reactor to undergo further reaction. Temperatures in the main flow reactor are varied independently to observe conditions needed to convert the initial polymer fragments to CO2 and H2O. Combustion products are monitored at main reactor temperatures from 400 to 850 °C and at 2.0-s total residence time with four on-line GC/FIDs; polymer reaction products and intermediates are further identified by GC/MS analysis. Analysis of polymer decomposition fragments at 400 °C encompasses complex oxygenated and aromatic hydrocarbon species, which range from high-molecular-weight intermediates of ca. 300 amu, through intermediate mass ranges down to C1 and C2 hydrocarbons, CO, and CO2. Approximately 41 of these species are positively identified for cellulose and 52 for polystyrene. Products from thermal oxidation of cellulose and polystyrene are shown to achieve complete combustion to CO2 and H2O at a main reactor temperature of 850 °C under fuel-lean equivalence ratio and 2.0-s reaction time. A dual-zone, continuous feed tubular reactor is developed to assess the potential for formation of products from incomplete combustion in thermal oxidation of common polymers. Solid polymer (cellulose or polystyrene) is fed continuously into a volatilization oven where it fragments and vaporizes. The gas-phase polymer fragments flow directly into a second, main flow reactor to undergo further reaction. Temperatures in the main flow reactor are varied independently to observe conditions needed to convert the initial polymer fragments to CO2 and H2O. Combustion products are monitored at main reactor temperatures from 400 to 850°C and at 2.0-s total residence time with four on-line GC/FIDs; polymer reaction products and intermediates are further identified by GC/MS analysis. Analysis of polymer decomposition fragments at 400°C encompasses complex oxygenated and aromatic hydrocarbon species, which range from high-molecular-weight intermediates of ca. 300 amu, through intermediate mass ranges down to C1 and C2 hydrocarbons, CO, and CO2. Approximately 41 of these species are positively identified for cellulose and 52 for polystyrene. Products from thermal oxidation of cellulose and polystyrene are shown to achieve complete combustion to CO2 and H2O at a main reactor temperature of 850°C under fuel-lean equivalence ratio and 2.0-s reaction time.
- Park, Byung-Ik,Bozzelli, Joseph W.,Booty, Michael R.,Bernhard, Mary J.,Mesuere, Karel,Pettigrew, Charles A.,Shi, Ji-Chun,Simonich, Staci L.
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p. 2584 - 2592
(2007/10/03)
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- Reduction of α-halo carbonyl compounds with NaBH4-SbBr3
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The reagent NaBH4-SbBr3 was found to be chemoselective for the reductive debromination of aromatic α-bromo carbonyl compounds and 2,3-dibromo-1,4-butanediones.
- Sayama, Shinsei,Inamura, Yutaka
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p. 633 - 634
(2007/10/03)
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- Phototransformations of C-benzoylaziridines. Dipolarophilic trapping of photogenerated azomethine ylides
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The phototransformations of a few 2,3-diaroylaziridines and 2-aryl-3-aroylaziridines have been studied by steady-state photolysis and product analysis.The formation of various photoproducts could be substantiated by ring opening via C-C bond cleavage (leading to azomethine ylides), intramolecular hydrogen abstraction, and C-N bond cleavage.Isolation of stereospecific 3-pyrrolidine derivatives from the photoreaction of benzoylaziridines in the presence of DMAD confirms our previous results concerning the azomethine ylides as major transient intermediates, produced under laser pulse photoexcitation.Dimethyl 1-cyclohexyl-2-benzoylpyrrole-3,4-dicarboxylate (25), one of the photoadducts derived from the reaction of 1a and 1b with DMAD undergoes a novel and unusual photoarrangement to give dimethyl 2-(1-benzoylcyclohexyl)pyrrole-3,4-dicarboxylate (27), the structure of which was confirmed through X-ray crystallographic analysis.
- Ramaian, D.,Muneer, M.,Gopidas, K. R.,Das, P. K.,Rath, N. P.,George, M. V.
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p. 4240 - 4246
(2007/10/03)
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- Reaction of Organohalogens with in situ Electrogenerated Superoxide Ion
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Superoxide ion, generated by electrochemical reduction of O2 in dimethylformamide at mercury cathode, reacts as an effective nucleophile with haloarenes (1a-4a) and as a base with phenacyl halides (5a and 6a) affording phenols (1a-4b) and trans-dibenzoylethene (5b) respectively.
- Dwivedi, Suchitra,Singh, Manorama,Misra, Ram Achal
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- Reaction of N-fluoropyridinium salts with Wittig reagents: A novel and convenient approach to symmetric trans-olefins
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N-Fluoropyridinium salts were found to react with Wittig reagents containing electron-withdrawing groups to give olefins in 47-83% yield. The mechanism of this conversion is believed in involve single-electron transfer from Wittig reagent to N-fluoropyridinium cation.
- Kiselyov, Alexander S.
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p. 8951 - 8954
(2007/10/02)
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- Palladium-Catalyzed Reductive Coupling of Acid Chlorides with β-Stannyl Enones: Synthesis of 1,4-Diketones and Mechanistic Aspects
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The palladium-catalyzed coupling of acid chlorides with (E)-1,2-bis(tri-n-butylstannyl)ethene or β-stannyl enones gives butane-1,4-diones directly by reduction of the intermediate enedicarbonyl intermediate.The double bond conjugated with a single carbonyl group was not significantly reduced.The generality of the method is illustrated by two syntheses of the 1,4-diketone ipomeanine.By performing the reaction at lower temperatures, α,β-unsaturated 1,4-diketones can also be prepared.The reduction of the intermediate α,β-unsaturated 1,4-diketones probably proceeds by insertion of a palladium hydride, formed in situ by reaction of a Pd(II) complex with Bu3SnCl, followed by hydrolysis of the intermediate palladium enolate.
- Echavarren, Antonio M.,Perez, Marta,Castano, Ana M.,Cuerva, Juan M.
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p. 4179 - 4185
(2007/10/02)
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- STUDY OF THE ESCHENMOSER SULFIDE CONTRACTION METHOD WITH AND WITHOUT A THIOPHILE
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Results obtained and observations made by applying the title method for the synthesis of enaminones 5a-o, using triphenylphosphine as a thiophile and triethylamine as a base, are reported.The product distributions of the deprotonations of α-phenacylthio iminium bromides with and without thiophile and those known from thiouronium and heterocyclic thionium analogs are compared.Key words: Enaminones; α-phenacylthio iminium bromides; disulfides; thiiranes.
- Corsaro, A.,Perrini, G.,Testa, M. G.,Chiacchio, U.
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p. 197 - 206
(2007/10/02)
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- Synthesis of 1,4-Diketones by Palladium-Catalyzed Reductive Coupling of Acid Chlorides with (E)-1,2-Bis(tri-n-butylstannyl)ethene or β-Stannyl Enones
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The palladium-catalyzed coupling of acid chlorides with (E)-1,2-bis(tri-n-butylstannyl)ethene or β-stannyl enones gives butane-1,4-diones directly by reduction of the intermediate enedicarbonyl derivative by a palladium hydride derived from n-Bu3SnCl.
- Perez, Marta,Castano, Ana M.,Echavarren, Antonio M.
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p. 5047 - 5049
(2007/10/02)
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- Oxidation of Alkynes and Ylides by Oxo(salen)chromium(V) (salen=N,N'-ethylenebis-salicylideneiminato) Trifluoromethanesulphonate
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Oxo(salen)chromium(V) trifluoromethanesulphonate reacts with alkynes to afford diones, and with phosphorus ylides to afford aldehydes and ketones via similar organometallic intermediates.
- Rihter, B.,Masnovi, J.
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- Reactions of α-Diazoketones with Olefinic Compounds in Presence of Catalysts and Related Studies
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A relatively stable cyclopropane adduct is produced by trapping ketocarbenes in olefin.The reactivities of ketocarbenes prepared thermally from different α-diazoketones and of the olefin substrates, and the effect of different catalysts and solvents are some of the parameters which have a pronounced effect on the yield of the products.Besides the cyclopropane adducts some side products have also been isolated and characterized.
- Podder, Ranjan Kumar,Sarkar, Tarani Kanta,Sarkar, Ranjit Kumar,Ray, Suvas C.
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p. 217 - 224
(2007/10/02)
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- ORGANOPHOSPHORUS COMPOUNDS, 9. THE REACTION OF YLID-PHOSPHORANES WITH NITROSONAPHTHOLS
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α-Nitroso-β-naphthol (1a) reacts with ylid-phosphoranes 3a-c to give the corresponding imines 4a-c.On the other hand, β-nitroso-α-naphthol (1b) undergoes deoxygenative dimerization by the same reagents to yield the azo-derivative 6.The appropriate symmetrically disubstituted ethylene 7 was also isolated and identified in each reaction.Structures 4, 6 and 7 were attested by compatible analytical and spectroscopic results.
- Mahran, Mohamed R.,Abdou, Wafaa M.,Ganoub, Neven A. F.
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- Photochemical Transformations of 1-Imidazolyl-1,2-dibenzoylalkenes. Steady-State and Laser Flasch Photolysis Investigations
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The photochemistry of a number of 1-imidazolyl-1,2-dibenzoylalkenes and 1-benzimidazolyl-1,2-dibenzoylalkenes has been investigated by steady-state photolysis combined with product analysis and laser flash photolysis.In several cases, the intramolecular phenyl group migration leading to ketene-mediated 3-butenoic acids and esters is observed.In addition, depending on the substituents present in the imidazolyl and benzimidazolyl groups, a variety of phototransformations occur; these include electrocyclic ring-closure reactions leading to dihydrophenanthrene and dihydroisoquinoline derivatives and photofragmentation reactions resulting in the loss of the imidazolyl moieties from the parent dibenzoylalkenes.Plausible mechanisms for these photoreactions are discussed.Laser flash photolysis in several cases gives rise to transient processes related to ketene and zwitterionic intermediates.
- Barik, Rabindra,Bhattacharyya, Kankan,Das, Paritosh K.,George, Manapurathu V.
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p. 3420 - 3428
(2007/10/02)
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- Stereospecific Epoxidation of cis-2-Butene-1,4-diones to cis-2,3-Epoxybutane-1,4-diones with Oxodiperoxomolybdenum (VI), MoO5*H2O*HMPA
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The epoxidation of cis-2-butene-1,4-diones 4 with (aqua)(hexamethylphosphoramide)oxodiperoxomolybdenum (VI), MoO5*H2O*HMPA, occured stereospecifically to give the cis-epoxides 5, whose stereochemistry was assigned on the basis of chemical evidence and a comparision of their spectral data with those of the corresponding trans-epoxides 6, which were prepared by the epoxidation of the trans-olefins 3 with alkaline hydrogen peroxide.
- Chien, Chun-Sheng,Kawasaki, Tomomi,Sakamoto, Masanori,Tamura, Yasumitsu,Kita, Yasuyuki
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p. 2743 - 2749
(2007/10/02)
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- Oxidation of Furan, Pyrrole, Thiophene, Benzo furan, and Benzothiophene with Oxodiperoxomolybdenum (VI), MoO5*HMPA
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The oxidation of 2,5-diphenylfuran (1) with (hexamethylphophoramide)oxodiperoxomolybdenum(VI), MoO5*HMP, gave cis-1,4-diphenyl-2-butene-1,4-dione (2) and its cis-epoxide 3. 2,3-Diphenylpyrrole (4) was similarly treated with MoO5*HMPA to give the dimeric product 6, together with the cis-epoxide 3 and the trans-olefin 5.In the case of 2,5-diphenylthiophene (8), the oxidation with MoO5*HMPA occurred at the sulfur atom of 8 to give thiophene 1,1-dioxide (9).The oxidation of benzofuran (10) and benzothiophene (16) with MoO5*HMPA is also described.Keywords: furan; pyrrole; thiophene; benzofuran; benzothiophene; peroxomolybdenum complex; oxidation; epoxidation; dimerization
- Chien, Chun-Sheng,Kawasaki, Tomomi,Sakamoto, Masanori
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p. 5071 - 5074
(2007/10/02)
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- Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic N-Ylides with Symmetrically Substituted cis and trans Olefins
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Stereochemistry of the cycloadditions of twenty-four heteroaromatic N-ylides with several symmetrically substituted cis and trans olefins has been investigated.Cyclic and acyclic cis olefins cycloadd to the anti form of the ylides in a highly endo-selective manner giving almost quantitative yields of stereospecific endo 3+2 cycloadducts.N-Ylides stabilized with a substituent of carbonyl type react with trans olefins to form mostly two stereoisomeric 3+2 cycloadducts to the anti form of the ylides.In most cases, they undergo the stereospecific interconversion through a retro cycloaddition process, the isomer ratios and the easiness of transfromation depending upon the nature and size of substituents on the five-membered ring which has been built up in the cycloaddition step.On the other hand, N-ylides stabilized with a substituent of noncarbonyl type react with trans olefins to give stereospecific and stereoselective 3+2 cycloadducts as single isomers which are assigned as the cycloadducts to the syn form of the ylides.
- Tsuge, Otohiko,Kanemasa, Shuji,Takenaka, Shigeori
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p. 3137 - 3157
(2007/10/02)
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- Topical preparations for the treatment of seborrhea and process for inhibiting sebum production
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A topical cosmetic preparation for the treatment of seborrhea containing an antiseborrheically effective amount of at least one compound having the formula STR1 wherein Ar represents a member selected from the group consisting of phenyl, phenyl substituted with at least one group selected from the group consisting of alkyl having from 1 to 4 carbon atoms, alkoxy having from 1 to 4 carbon atoms, hydroxy and halo, naphthyl and heteroaromatic radical having from 4 to 5 carbon atoms in the cycle, and R represents a member selected from the group consisting of hydrogen, alkyl having from 1 to 4 carbon atoms, alkanoyl having from 1 to 4 carbon atoms, aryl and arylcarbonyl, where aryl has the same meaning as Ar, as an antiseborrheic, and further containing conventional vehicles and additives. The invention also relates to the process for reducing sebaceous cell sebum production employing said topical cosmetic preparation.
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- NEW C-C BOND FORMATION WITH PYRIDINIUM METHYLIDE: HYDROMETHYLENATION OF OLEFIN
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New C-C bond formation with pyridinium methylide is presented: Pyridinium methylide reacts with electron-deficient olefins providing the next higher homologs of olefins, in which the double bond of starting olefin is saturated and, instead, a C=C double bond is newly formed.This reaction mode has been never reported before in the study of nitrogen ylide and is to be referred to as hydromethylenation of olefin.In the presence of base, 1,2-double bond migration occurs leading to the methylated derivatives of starting olefins.
- Tsuge, Otohiko,Kanemasa, Shuji,Kuraoka, Satoru,Takenaka, Shigeori
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p. 281 - 284
(2007/10/02)
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- Base-catalysed Rearrangements involvung Ylide Intermediates. Part 8. The Preparation and Some Reactions of Stable Ammonium Ylides
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The carbonyl-stabilised ammonium ylides (3), (12a-n), and (14a-c) were obtained from the reaction of the corresponding ammonium halides (1), (13a-n), and (15a-c) with sodium hydroxide in water or aqueous methanol.The ylides, which were characterised by their molecular formulae and spectroscopic properies, regenerated quaternary ammonium bromides on treatment with hydrobromic acid.In general the reactions of the ammonium ylides resemble those of the corresponding sulphonium ylides.Thus ylides having a suitable migrating group (ArCH2) undergo a Stevens rearrangement on heating, and other ylides fragment to give a tertiary amine and products containing the PhCOCH grouping.A number of ylides reacted with dimethyl acetylenedicarboxylate to give the furans (32).The ylides (14b and c) with phenyl isocyanate gave the phenylcarbamoyl-substituted ylides.
- Jemison, Robert W.,Mageswaran, Sivapathasuntharam,Ollis, W. David,Sutherland, Ian O.,Thebtaranonth, Yodhathai
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p. 1154 - 1164
(2007/10/02)
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- ONE STEP SYNTHESIS OF AZIRIDINES BY THE MICHAEL TYPE ADDITION OF FREE SULFIMIDES
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The Michael type additions of diphenyl N-unsubstituted sulfimide (free sulfimide) to various electrophilic olefins were carried out.The reaction with cis- and trans-dibenzoylethylene, dimethylfumarate, dimethylmaleate, benzalacetophenone and benzalacetone gave mainly the corresponding trans-2-acylaziridines and trans-enaminoketones.However, phenyl vinyl sulfone or acrylonitrile afforded not the corresponding aziridine but diphenyl-N-2-cyano or N-2-phenylsulfonylethylsulfimide, a simple Michael adduct.When optically active (+)-(R)-o-methoxyphenylphenyl free sulfimide was treated with such an α,β-unsaturated carbonyl compound as benzalacetophenone, an optically active 2-acylaziridine, i.e., (-)-trans-2-benzoyl-3-phenylaziridine was obtained in ca 30percent optical purity and its absolute configuration was assigned as (2R,3S) upon chemical transformation to the configurationally known 2-phenyl-2-benzoylamino-1-ethanol or by comparing its CD spectrum with that of (1R,2R)-1-phenyl-2-benzoyl-cyclopropane.Meanwhile, (-)-(S)-o-methoxyphenylphenyl free sulfimide was found to react with benzalacetophenone to afford (+)-trans-2-benzoyl-3-phenylaziridine of 25percent optical purity.Effects of solvent and temperature on both the distribution of the products ratio and the optical yield were examined.
- Furukawa, Naomichi,Yoshimura, Toshiaki,Ohtsu, Masami,Akasaka, Takeshi,Oae, Shigeru
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