- Unexpected formation of 4,4-dimethyl-1,2-disubstituted-dicarbonyl cyclopentanes from ketone enolate anions and 1,3-diiodo-2,2-dimethylpropane
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Cyclic 1,4-dicarbonyl compounds can be easily obtained by mixing a solution of aryl methyl or alkyl methyl ketone enolate anions with 1,3-diiodo-2,2-dimethylpropane in DMSO. This represents the first example of dimerization of ketone enolate anions using a simple diiodoalkane as a reagent followed by subsequent double alkylation with bis-iodide yielding a cyclopentane adduct. This methodology allows the use of a simple potassium tert-butoxide as a base at room temperature for the formation of three C-C bonds resulting in a relatively complex five-membered ring diketone structure under transition-metal-free conditions.
- Barrionuevo, Cecilia A.,Schmidt, Luciana C.,Argüello, Juan E.
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- Novel photo-rearrangement of 1,5-di(p-methoxyphenyl)-6,7-dioxabicyclo[3.2.2]nonane through an O-neophyl-type 1,2-aryl shift: Evidence for a 1,6-dioxyl diradical intermediate
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Photolysis and thermolysis of 1,5-diaryl-6,7-dioxabicyclo[3.2.2]nonane 1a-c (a: Ar=p-MeOC6H4, b: Ar=p-MeC6H4, c: Ar=Ph) were investigated. (p-Methoxyphenyl)-substituted 1a underwent a novel photo-initiated O-neophyl-type 1,2-aryl shift to afford 1-(p-methoxyphenyl)oxy-5-(p-methoxyphenyl)-8-oxabicyclo[3.2.1]octane 7a along with a small amount of 1-(p-methoxyphenyl)-3-(2-(4′-methoxyphenyl)tetrahydrofuran-2-yl) propan-1-one 4a through an 1,6-dioxyl diradical intermediate, while the thermolysis mainly afforded the 1,5-di(p-methoxyphenyl)pentan-1,5-dione 5a and 1,4-di(p-methoxyphenyl)butan-1,4-dione 8a.
- Kamata, Masaki,Komatsu, Ken-Ichi
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- Asymmetric hydrogenation of 1,4-diketones: facile synthesis of enantiopure 1,4-diarylbutane-1,4-diols
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Owing to the biological significance and great synthetic value of 1,4-diarylbutane-1,4-diols and their derivatives, increasingly considerable attention has been paid to developing effective synthetic methods for chiral 1,4-diarylbutane-1,4-diols. We herei
- Huang, Fanping,Shao, Pan-Lin,Song, Jingyuan,Wang, Jiang,Zhang, Xumu
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supporting information
p. 262 - 265
(2022/01/06)
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- Copper(I)/DDQ-Mediated Double-Dehydrogenative Diels-Alder Reaction of Aryl Butenes with 1,4-Diketones and Indolones
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A copper(I)/DDQ-mediated double-dehydrogenative Diels-Alder (DDDA) reaction of simple butenes with 1,4-diketones and indolones has been established for the first time. This strategy is based on a tandem double-dehydrogenation/Diels-Alder reaction from nonprefunctionalized starting materials, in which both a diene and dienophile were in situ generated via activation of fourfold inert C(sp3)-H bonds in one catalytic system.
- Chen, Jie,Hu, Wei,Wang, Min,Xu, Wen-Lei,Zhao, Wei-Ming,Zhou, Ling
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supporting information
p. 7169 - 7174
(2020/10/12)
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- Synthesis of 2,2,5-Trisubstituted 2 H-Pyrroles and 2,3,5-Trisubstituted 1 H-Pyrroles by Ligand-Controlled Site-Selective Dearomative C2-Arylation and Direct C3-Arylation
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Palladium-catalyzed site-selective dearomative C2-arylation of 2,5-diaryl-1H-pyrroles with aryl chlorides was accomplished, and a series of 2,2,5-triaryl-2H-pyrroles were synthesized. In addition, the site selectivity of the reaction was switched by simply changing the ligand, and the direct C3-arylated 2,3,5-triaryl-1H-pyrroles were prepared. The obtained 2,2,5-triaryl-2H-pyrroles could be further transformed into 2,2,5,5-tetraarylpyrrolidines.
- Yamaguchi, Miyuki,Fujiwara, Sakiko,Manabe, Kei
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supporting information
p. 6972 - 6977
(2019/09/03)
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- Synthesis of 1,4-Diketones via Titanium-Mediated Reductive Homocoupling of α-Haloketones
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1,4-Diketones have been synthesized via a reductive homocoupling of α-haloketones. Addition of a Grignard reagent to titanium(IV) isopropoxide affords a low-valent titanium(III) intermediate that is believed to mediate a radical dimerization reaction. The
- Le, Nathan N.,Rodriguez, Aimee M.,Alleyn, James R.,Gesinski, Michael R.
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p. 2195 - 2198
(2018/09/29)
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- A novel coupling reaction of α-halo ketones promoted by SmI3/CuI
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With SmI3 as the Lewis acid and catalyzed by CuI in DMF, α-haloketones were transformed unexpectedly into α-hydroxy-1,4-diketones in good to moderate yields. The mechanism was probed and a plausible reaction pathway was proposed. DMF was assumed to play a dual role both as a hydroxyl source and as a solvent.
- Liu, Yongjun,Zhao, Hengmin,Tian, Guang,Du, Feng,Qi, Yan,Wen, Yonghong
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p. 26317 - 26322
(2016/03/25)
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- Breaking bonds with electrons: Stepwise and concerted reductive cleavage of C-S, C-Se and Se-CN bonds in phenacylthiocyanates and phenacylselenocyanates
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The mechanistic aspects of the electrochemical reduction of phenacylthio- and selenocyanates have been studied. With phenacylthiocyanates (1), a change in the reductive cleavage mechanism is observed as a function of the substituent on the phenyl ring. While a stepwise mechanism involving the intermediacy of a radical anion is followed for substrates bearing a strong electron withdrawing group, such as cyano and nitro substituent (1d, 1e), and a concerted mechanism is favoured for compounds bearing an electron-donating or no substituent on the phenyl ring (1a-c). A regioselective bond cleavage leads to the fragmentation of the CH2-S bond with all compounds 1a-e, further yielding the corresponding 1,4-diketone (3) as products. Contrastingly, with phenacylselenocyanates (2), two different reductive cleavages occur involving the breaking of both the CH2-Se and Se-CN bonds. Several products are obtained, all coming from nucleophilic attack at the α (phenacyl) carbon or the selenium atom.
- Bouchet, Lydia M.,Peory, Alicia B.,Robert, Marc,Argüello, Juan E.
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p. 11753 - 11760
(2015/02/19)
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- Polymer-stabilized palladium nanoparticles for the chemoselective transfer hydrogenation of α,β-unsaturated carbonyls: Single-step bottom-Up approach
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Polypyrrole stabilised palladium nanoparticles show good catalytic efficiency for the chemoselective transfer hydrogenation of α,β- unsaturated carbonyl compounds. The catalyst is very specific and selectively hydrogenates the olefins or acetylenes only,
- Mahato, Sanjit K.,Ul Islam, Rafique,Acharya, Chiranjit,Witcomb, Michael J.,Mallick, Kaushik
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p. 1419 - 1426
(2014/05/20)
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- Visible-light-induced Ci-S bond activation: Facile access to 1,4-diketones from β-ketosulfones
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A novel method for the synthesis of 1,4-diketones from β-ketosulfones was developed by means of a visible light-induced Ci£S bond activation process. Symmetrical and unsymmetrical 1,4-diketones can be easily prepared in moderate to good yields. A new and efficient method for the synthesis of 1,4-diketones from β-ketosulfones was developed by means of a visible-light-induced Ci£S bond activation process (see scheme). Symmetrical and unsymmetrical 1,4-diketones can be easily prepared in moderate to good yields.
- Xuan, Jun,Feng, Zhu-Jia,Chen, Jia-Rong,Lu, Liang-Qiu,Xiao, Wen-Jing
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supporting information
p. 3045 - 3049
(2014/03/21)
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- Woollins reagent: A chemoselective reducing agent for 1,4-enediones and 1,4-ynediones to saturated 1,4-diones
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Woollins reagent was found to act as a highly chemoselective reagent for the reduction of a wide range of 1,4-enediones and 1,4-ynediones in methanol to afford the corresponding saturated 1,4-diketones in good yields under mild reaction conditions.
- Mandal, Madhumita,Chatterjee, Sourav,Jaisankar, Parasuraman
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supporting information
p. 2615 - 2618,4
(2012/12/12)
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- Efficient synthesis of γ-keto sulfones by NHC-catalyzed intermolecular Stetter reaction
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The N-heterocyclic carbene-catalyzed intermolecular Stetter reaction of aldehydes with α,β-unsaturated sulfones allows the atom-economic and selective formation of γ-keto sulfones in good yields. Key to the success of this unique transition-metal-free carbon-carbon bond-forming reaction is the right choice of the NHC precursor and base. The reaction tolerates a broad range of different aldehydes.
- Bhunia, Anup,Yetra, Santhivardhana Reddy,Bhojgude, Sachin Suresh,Biju, Akkattu T.
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supporting information; experimental part
p. 2830 - 2833
(2012/07/17)
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- Photochemistry of S -phenacyl xanthates
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Various synthetically readily accessible S-phenacyl xanthates are shown to undergo photoinitiated homolytic scission of the C-S bond in the primary step. The resultant fragments, phenacyl and xanthic acid radicals, recombine to form symmetrical 1,4-diketones and xanthogen disulfides, respectively, in high to moderate chemical yields in chemically inert solvents. They can also be efficiently trapped by a hydrogen-atom-donating solvent to give acetophenone and xanthic acid derivatives. The latter compound is in situ thermally converted to the corresponding alcohol in high chemical yields. S-Phenacyl xanthates could thus be utilized as synthetic precursors to the above-mentioned compounds or as photoremovable protecting groups for alcohols in which the xanthate moiety represents a photolabile linker. The photochemically released phenacyl radical fragments efficiently but reversibly add to the thiocarbonyl group of the parent xanthate molecule. The kinetics of this degenerative reversible addition-fragmentation transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) mechanism was studied using laser flash photolysis (LFP) and density functional theory (DFT) calculations. The rate constants of the RAFT addition step, kadd ~ 7 × 108 M-1 s-1, and phenacyl radical addition to a double bond of 1,1-diphenylethylene, kadd ~ 108 M-1 s -1, in acetonitrile were experimentally determined by LFP. In addition, photoinitiation of the methyl methacrylate polymerization by S-phenacyl xanthate is demonstrated. The polydispersity index of the resulting poly(methyl methacrylate) was found to be ~1.4. We conclude that S-phenacyl xanthates can serve simultaneously as photoinitiators as well as RAFT/MADIX agents in polymerization reactions.
- Tazhe Veetil, Aneesh,Solomek, Tomas,Ngoy, Bokolombe Pitchou,Pavlikova, Nela,Heger, Dominik,Klan, Petr
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p. 8232 - 8242
(2012/01/03)
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- Synthesis of water-tolerant indium homoenolate in aqueous media and its application in the synthesis of 1,4-dicarbonyl compounds via palladium-catalyzed coupling with acid chloride
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The first water-tolerant, ketone-type indium homoenolate was synthesized via the oxidative addition of In/InCl3 to enones. The reaction proceeds exclusively in aqueous media. Both indium and indium(III) chloride are necessary for the smooth conversion of the reaction. Similar results were obtained when InCl or InCl2 was used in place of In/InCl3. The synthetic utility of the indium homoenolate was demonstrated through the synthesis of 1,4-dicarbonyl compounds via palladium-catalyzed coupling of indium homoenolate with acid chloride.
- Shen, Zhi-Liang,Goh, Kelvin Kau Kiat,Cheong, Hao-Lun,Wong, Colin Hong An,Lai, Yin-Chang,Yang, Yong-Sheng,Loh, Teck-Peng
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supporting information; experimental part
p. 15852 - 15855
(2011/01/10)
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- Synthesis of 1,4-diketones: reaction of α-bromo ketones with tetrakis(dimethylamino)ethylene (TDAE)
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1,4-Diketones were prepared by the reaction of α-bromo ketones with tetrakis(dimethylamino)ethylene (TDAE) in moderate to good yields. Similarly, α-bromo esters were reductively coupled using TDAE to give the 1,4-diesters in moderate yields.
- Nishiyama, Yutaka,Kobayashi, Akihiro
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p. 5565 - 5567
(2007/10/03)
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- Triphenylpyrylium salt-sensitized photoreactions of 1,4-diaryl-2,3- dioxabicyclo[2.2.2]octanes through competitive single electron-transfer pathway and proton-catalyzed pathway
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2,4,6-Triphenylpyrylium tetrafluoroborate (TPPBF4)-sensitized photoinduced electron-transfer (PET) reactions of 1,4-diaryl-2,3-dioxabicyclo[2. 2.2]octanes 5 (a: Ar1 = Ar2 = p-MeOC6H 4, b: Ar1 = Ar2 = p-MeC6H 4, c: Ar1 = Ar2 = Ph) underwent novel fragmentation through their radical cations to give 1,4-diarylbutan-1,4-diones 6 accompanied by elimination of ethylene. On the other hand, 4-aryl-cyclohex-3- en-1-ones 7, p-substituted phenols 8, and 4-aryl-4-aryloxycyclohexanones 9 were produced through proton-catalyzed pathways when the PET reactions of 5 were performed in the absence of a certain base such as 2,6-di-tert-butylpyridine (DTBP). Particularly, the formation of 9 is consistent with the novel cationic rearrangement involving nucleophilic O-1,2-aryl shifts and C-1,4-aryl shifts.
- Kamata, Masaki,Kaneko, Jun-Ichi,Hagiwara, Jun-Ichi,Akaba, Ryoichi
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p. 7423 - 7428
(2007/10/03)
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- Indium(I) bromide-mediated reductive coupling of α,α- dichloroketones to 1-aryl-butane-1,4-diones
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Indium(I) bromide promotes the reductive coupling of α,α- dichloroketones to the corresponding 1,4-butanediones in moderate to good yields.
- Peppe, Clovis,Pav?o Das Chagas, Rafael
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p. 1187 - 1190
(2007/10/03)
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- Fe(II)-mediated fragmentation of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes through competitive single electron transfer pathway and Lewis acid pathway
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Reactions of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes 1a-d (1a: Ar=p-FC6H4, 1b: Ar=Ph, 1c: Ar=p-MeC6H4, 1d: Ar=p-MeOC6H4) with FeBr2 in THF afforded 1,4-diarylbutan-1,4-diones 2a-d and 1,4-diaryl-7-oxabicyclo[2.2.1]heptanes 3a-d. On the other hand, 4-aryl-3-cyclohexenones 4c-d and p-substituted phenols 5c-d were obtained in the reactions of 1c-d with FeBr2 in CH2Cl2. A new fragmentation mechanism involving an electrophilic oxyl radical 1,5-substitution and a nucleophilic O-1,2-aryl shift is proposed based on the product analysis. In addition, the in vitro antimalarial activities of 1a-d were tested.
- Kamata, Masaki,Kudoh, Takashi,Kaneko, Jun-Ichi,Kim, Hye-Sook,Wataya, Yusuke
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p. 617 - 620
(2007/10/03)
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- Media controlled photo - Favorskii type rearrangement of α-chloro acetophenones: Synthesis of phenylacetic acids
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Photolysis of substituted α-chloro acetophenones has been studied in different solvent systems wherein 1,2-aryl migration is found to be media controlled. Effect of substituents on the migratory aptitude and a direct access to phenylacetic acids, in practical yields, has been described.
- Dhavale, Dilip D.,Mali, Vasant P.,Sudrik, Surendra G.,Sonawane, Harikisan R.
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p. 16789 - 16794
(2007/10/03)
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- The Reaction of Arylmagnesium Halides with Succinic Anhydride
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The reaction of equimolar amounts of phenylmagnesium bromide and succinic anhydride in THF at -78 deg for 2 h gives subsequent to hydrolytic work-up, 3-benzoylpropionic acid in 76percent yield and 4,4-diphenyl-4-butyrolactone in 3percent yield.When two molar equivalents of the Grignard reagent are employed, the yields of these products are respectively 85 and 14percent.On the other hand, when four equivalents of the Grignard reagent are employed for every equivalent of succinic anhydride at 66 deg C, a diketone, 1,4-diphenylbutane-1,4-dione is obtained in 72percent yield.Other products include 4,4-diphenyl-4-butyrolactone (19percent) and 3-benzoylpropionic acid (6percent).Under comparable conditions, 4-methyl- and 4-methoxyphenylmagnesium halides react similarly with succinic anhydride, giving fair yields (49-53percent) of the corresponding diketones.However, 4-chlorophenylmagnesium chloride only gives the keto-acid (12percent) and lactone (42percent), but no diketone.
- Rahman, M. T.,Nur, H. P.
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p. 469 - 474
(2007/10/02)
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- Reactions of carbanions from 2-(dialkylamino)-arylacetonitriles with acetylene - Simple syntheses of 1,3-dienamines and 1,4-diketones
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It has been found that morpholinonitrile 1a reacts with acetylene (2) in the presence of solid sodium hydroxide and tetrabutylammonium bromide (TBABr) as a catalyst, in DMSO, to give the vinyl derivative 3a. Whereas aminonitriles 1b-i, in the reaction with 2, afford dienamines 7. The different reactivity of 1a as compared to 1b-i is explained in terms of the different basicity of the amino moiety in vinyl derivatives 3. Dienamines 7 were hydrolyzed to 1,4-diarylbutan-1,4-diones 8 in high yields.
- Jonczyk, Andrzej,Lipiak, Dariusz,Zdrojewski, Tadeusz
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p. 1025 - 1038
(2007/10/02)
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- Carbon-Carbon Bond Formation Using Hypervalent Iodine Under Lewis Acid Conditions: Scope of the Method for the Synthesis of Butane-1,4-diones
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Hypervalent iodine oxidation of the silyl enol ethers of various acetophenones (2a-g), 2-acetylthiophenes (2i-k), 2-acetylfuran (2l) and 2-acetylbenzofuran (2m) with iodosobenzene-boron trifluoride-diethyl ether results in carbon-carbon coupling to yield the corresponding 1,4-disubstituted butane-1,4-dione (3a-m).Cross coupling (dissimilar coupling) between 4-methoxyacetophenone silyl enol ether (2c) and 4-nitroacetophenone silyl enol ether (2e) affords 1-(4-methoxyphenyl)-4-(4-nitrophenyl)butane-1,4-dione (27percent); the other minor products (3c) (18percent) and (3e) (15percent) resulting from similar coupling in this reaction.The sterically hindered aliphatic silyl enol ether (2h) obtained from pinacolone also undergoes smooth coupling whereas other aliphatic ketones do not.This method is likewise unsuccessful in case of nitrogen-containing heterocycles, viz. 2-,3-,4-acetylpyridine silyl enol ethers and tropinone silyl enol ether.
- Moriarty, Robert,Prakash, Om,Duncan, Michael P.
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p. 559 - 562
(2007/10/02)
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- Addition von Aldehyden an aktivierte Doppelbindungen, XXIX. Neue Methode zur Darstellung symmetrischer 1,4-Diketone
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Thiazolium salt-catalysed addition of aliphatic, aromatic, and heterocyclic aldehydes to phenyl vinyl sulfone yields in a three-step addition-elimination mechanism 1,4-diketones (1 - 3) and 1,4-disulfone (23).The analogous reaction with divinyl sulfone leads in good yields to the corresponding 1,4-diketones (1 - 22).
- Stetter, Hermann,Bender, Hans-Juergen
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p. 1226 - 1233
(2007/10/02)
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- Quinone Dehydrogenation. Oxidation of Benzylic Alcohols with 2,3-Dichloro-5,6-dicyanobenzoquinone
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2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) reacts with primary and secondary aryl-substituted alcohols under mild conditions in dioxane solution to give the corresponding carbonyl compounds in high yields.In contrast to other oxidants, DDQ can be applied advantageously for the oxidation of hydroxyaryl-substituted alcohols.A mechanism involving participation of the phenolic hydroxyl group in the dehydrogenation reaction is discussed.Oxidations of hydroxyaryl-substituted alcohols by DDQ in methanolsolution resulting in the formation of benzoquinones by loss of the hydroxyaryl side chain are interpreted in terms of phenol oxidation.An example of a pyridine-catalyzed Smiles rearrangement of an o-hydroxy-substituted diphenyl ether is reported.
- Becker, Hans-Dieter,Bjoerk, Anders,Adler, Erich
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p. 1596 - 1600
(2007/10/02)
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