- Phosphorus(III)-Mediated, Tandem Deoxygenative Geminal Chlorofluorination of 1,2-Diketones
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Tetrasubstituted carbon containing two different halogen substituents was constructed in a single-step operation by utilizing the carbene-like reactivity of dioxaphospholene through the tandem reaction of electrophilic and nucleophilic halogenating reagents. It was crucial to devise non-dealkylatable phosphoramidite, which enabled the efficient formation of geminal chlorofluorides from various 1,2-diketones with (PhSO2)2NF and n-Bu4NCl. In addition, selective functionalization of the chlorine substituent was demonstrated, and the absence of halogen scrambling was confirmed.
- Choi, Garam,Chung, Won-Jin,Hwang, Sunjoo,Jang, Hanna,Kim, Ha Eun
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p. 4190 - 4195
(2020/06/27)
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- Visible light promoted continuous flow photocyclization of 1,2-diketones
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The continuous flow Norrish-Yang photocyclization of 1,2-diketones has been developed and used for the synthesis of a large number of functionalized 2-hydroxycyclobutanones, under blue light irradiation and employing acetone as a solvent. This eco-friendly procedure represents a valid alternative to the reactions carried out in batches thus reducing the reaction times, the formation of secondary products and simplifying the purification steps. The use of differently substituted diketone compounds has allowed us to obtain a wide range of 2 and 3-functionalized cyclobutanones, thus allowing the evaluation of the scope and limitations of this procedure.
- Frongia, Angelo,Luridiana, Alberto,Porcu, Stefania,Ricci, Pier Carlo,Secci, Francesco
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supporting information
p. 3684 - 3689
(2020/06/03)
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- A Nucleophilic Strategy for Enantioselective Intermolecular α-Amination: Access to Enantioenriched α-Arylamino Ketones
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The enantioselective addition of anilines to azoalkenes was accomplished through the use of a chiral phosphoric acid catalyst. The resulting α-arylamino hydrazones were obtained in good yields and excellent enantioselectivities and provide access to enantioenriched α-arylamino ketones. A serendipitous kinetic resolution of racemic α-arylamino hydrazones is also described.
- Miles, Dillon H.,Guasch, Joan,Toste, F. Dean
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p. 7632 - 7635
(2015/07/02)
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- Catalytic oxidation of silyl enol ethers to 1,2-diketones employing nitroxyl radicals
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A novel and efficient method for the preparation of 1,2-diketones is reported. A series of -diketones were readily prepared by the nitroxyl-radical-catalyzed oxidation of silyl enol ethers using magnesium monoperoxyphthalate hexahydrate (MMPP6H) as the co-oxidant. Georg Thieme Verlag Stuttgart · New York.
- Hayashi, Masaki,Shibuya, Masatoshi,Iwabuchi, Yoshiharu
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p. 1025 - 1030
(2012/06/04)
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- Palladium-catalyzed carbonation-diketonization of terminal aromatic alkenes via carbon-nitrogen bond cleavage for the synthesis of 1,2-diketones
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A palladium-catalyzed carbonation-diketonization reaction of terminal alkenes via carbon-nitrogen bond cleavage under an atmosphere of oxygen has been developed. A series of 1,2-diketones were readily prepared from the reaction of aromatic terminal alkenes with nitroalkanes.
- Wang, Azhong,Jiang, Huanfeng,Li, Xianwei
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supporting information; experimental part
p. 6958 - 6961
(2011/10/02)
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- Enantioselective aerobic oxidation of α-hydroxy-ketones catalyzed by oxidovanadium(V) methoxides bearing chiral, N-salicylidene- tert -butylglycinates
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Chiral oxidovanadium(V) methoxides prepared from 3,5-disubstituted-N- salicylidene-l-tert-butylglycines and vanadyl sulfate in air-saturated MeOH serve as highly enantioselective catalysts for asymmetric aerobic oxidations and kinetic resolution of alkyl, aryl, and heteroaryl α-hydroxy-ketones with differed α-substituents at ambient temperature in toluene or TBME (tert-butyl methyl ether). The best scenarios involve the use of complexes which bear the tridendate templates derived from 3,5-diphenyl- or 3-o-biphenyl-5-nitro-salicyaldehyde. The kinetic resolution selectivities of the aerobic oxidation process are in the range of 12 to >1000 based on the selectivity factors (krel).
- Chen, Chien-Tien,Kao, Jun-Qi,Salunke, Santosh B.,Lin, Ya-Hui
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- Oxidation of alkynes in aqueous media catalyzed by diphenyl diselenide
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In this communication we propose a convenient methodology to effect the oxidation of alkynes using ammonium persulfate and diphenyl diselenide as catalyst. The reactions effected in aqueous media lead to 1,2-unprotected dicarbonyl derivatives or to hemiacetals starting from terminal alkynes.
- Santoro, Stefano,Battistelli, Benedetta,Gjoka, Blerina,Si, Chun-Wing Steven,Testaferri, Lorenzo,Tiecco, Marcello,Santi, Claudio
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scheme or table
p. 1402 - 1406
(2010/07/14)
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- Gold(I)-catalyzed oxidative rearrangements
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A series of gold(I)-catalyzed oxidative rearrangement reactions of alkynes using sulfoxides as stoichiometric oxidants are reported. The reactions are postulated to proceed through intermolecular oxygen atom transfer from the sulfoxide to gold(I)-carbenoi
- Witham, Cole A.,Mauleon, Pablo,Shapiro, Nathan D.,Sherry, Benjamin D.,Toste, F. Dean
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p. 5838 - 5839
(2008/02/12)
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- A Highly Efficient Ruthenium-Catalyzed Rearrangement of α,β-Epoxyketones to 1,2-Diketones
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TpRuPPh3(CH3CN)2PF6 catalyzed the efficient rearrangement of α,β-epoxyketones to 1,2-diketones. Unlike a previously reported iron catalyst, the reaction in this case is applicable not only to 1,2-disubstituted epoxides but also to mono- and trisubstituted epoxides and tolerates oxygen functionalities. The sterically crowded and highly basic tris(1-pyrazolyl)borate (Tp) ligand of the ruthenium catalyst might account for its high selectivity toward 1,2-diketone rather than 1,3-diketone.
- Chang, Chia-Lung,Kumar, Manyam Praveen,Liu, Rai-Shung
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p. 2793 - 2796
(2007/10/03)
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- Chemistry of singlet oxygen. Dye-sensitized photooxygenation of arylallenes
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1-Arylallenes react with singlet oxygen via 1,2-and 1,4-cycloaddition modes giving rise to three types of carbonyl fragments. 1,1-Diphenyl- and 1-phenylallenes react predominantly by the 1,4-mode. Plausible mechanisms are discussed for the formation of the observed products.
- Erden,Martinez
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p. 1859 - 1862
(2007/10/02)
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- SYNTHESIS OF α-DAMASCONE AND 1-(2,6,6-TRIMETHYL-2-TETRAHYDROPYRANYL)-2-ALKEN-1-ONES
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α-Damascone was obtained by the reaction of α-cyclocitral with allyl bromide in the presence of zinc, followed by oxidation of the obtained alcohol with chromic acid to the ketone and isomerization of the latter with triethylamine as catalyst.The analogous synthesis of β-damascone from 1-(4,6,6-trimethyl-1,3-cyclohexadienyl)-2-buten-1-one was impossible on account of complications at the oxidation stage.The rearrangement of the acetylenic alcohols with polyvanadioorganosiloxane as catalyst led to 1-(2,6,6-trimethyl-2-tetrahydropyranyl)-2-alken-1-ones.
- Erman, M. B.,Pribytkova, I. M.,Gulyi, S. E.,Bogomolova, O. A.,Cherkaev, G. V.,et al.
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p. 2294 - 2301
(2007/10/02)
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- A Facile One-Pot Synthesis of Vicinal Di- and Triketones from α-Methylene Ketones by NBS-DMSO Oxidation
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The reaction of 1,2-diarylethanones (1a-u) with N-bromosuccinimide in anhydrous dimethyl sulphoxide afforded diarylethanediones (2a-u) in excellent yields.Under similar conditions, 1-phenyl-2-butanone (3) gave 1-phenyl-1,2-butanedione (4) in fair yield in addition to a small amount of 1-phenyl-3-methylthio-1,2-butanedione (5) and 1-phenyl-1-methylthio-2-butanone (6). 4-Phenyl-2-butanone (7), 1,3-diphenyl-2-propanone (9), and 1,3-diphenyl-1,3-propanedione (10) gave the corresponding triketones monohydrate (8) and (11). 1-Indanone (12), 2-indanone (13), and 1,3-indandione (14) gave ninhydrin (15) in good yields.In the case of 3-phenyl-1-indanone (16), 3-phenyl-2-bromo-1-indanone (17), 3-phenyl-2-bromo-1-indenone (18) and 3-phenyl-1-indenone (19) were obtained. 1-Phenyl-1-propanone (20) and 1-phenyl-1-butanone (22) gave the corresponding α-(methylthio)ketones (21) and (22). 1,3,3-Triphenylpropanone (24a) and 1-phenyl-3-methyl-1-butanone (24b) yielded only the corresponding α-bromoketones (25a,b) in good yields.These α-bromoketones, however, afforded the corresponding α-diketones (26a,b) in moderate yields when α-bromoketones reacted with dimethyl sulphoxide in the presence of AgBF4.
- Tatsugi, Jiro,Izawa, Yasuji
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p. 2747 - 2763
(2007/10/02)
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- Studies on the Oxidative Cleavage of the CC Triple Bond during the Autoxidation of Acetylenic Hydrocarbons 1. Evidence for α-Dicarbonyl Compounds as Intermediates
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Examination of oxidation mixtures of 1-phenylprop-1-yne, 1-phenylbut-1-yne and 1-phenyl-3-methylbut-1-yne revealed the presence of hitherto not reported interesting products, especially the α-dicarbonyl compounds 1-phenylpropane-1,2-dione, 1-phenylbutane-1,2-dione and 1-phenyl-3-methylbutane-1,2-dione respectively in minor quantities.Some other typical products like benzil, benzoic anhydride and phenyl benzoate were also characterized.Although the oxidation of diphenylacetylene is very slow, benzil could be found as the main detectable product along with traces of benzoic acid.The α-diketones corresponding to the 1-phenylalk-1-ynes were oxidized at 110 deg C.In each case benzoic acid and the lower carboxylic acids as in the case of the autoxidation of the corresponding acetylenes were obtained.Benzil, benzoic anhydride and phenyl benzoate were also characterized in all the cases.Therefore, α-diketones are considered as intermediates responsible for the formation of the oxidative cleavage products of the CC triple bond.
- Rao, T. S. S.,Pritzkow, W.
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p. 474 - 482
(2007/10/02)
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- A VERSATILE ACCESS TO UNSYMMETRICAL AND SYMMETRICAL α-DIKETONES VIA ORGANOTIN REAGENTS
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Unsymmetrical α-diketones have been obtained via cross coupling of acyltins with acyl halides under PdCl2(PPh3)2 catalysis while symmetrical α-diketones have been readily obtained via "in situ" formation of acyltins using hexabutylditin and acyl chlorides under similar experimental conditions.
- Verlhac, Jean-Baptiste,Chanson, Evelyne,Jousseaume, Bernard,Quintard, Jean-Paul
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p. 6075 - 6078
(2007/10/02)
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- Medium-ring Ketone Synthesis. Intramolecular Acylation of Sulfur-stabilized Carbanions: A Model Study
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Intramolecular acylation of the sulfur-stabilized carbanions of the acyclic ester 9 and amide sulfides 11 was carried out as a model study for developing an effective method for the construction of medium-ring ketones by ring closure.Reaction of 9a-c or 11a-g with lithium diisopropylamide (LDA) proceeded smoothly and the expected keto sulfides 10a-c or 12a-g, respectively, were obtained.In the cases where R1 and/or R2 in 11 were normal alkyl groups, the reaction did not take place.However, these difficulties were readily overcome either by introducing a methyl group next to the carbonyl group or by converting the sulfides into the corresponding sulfoxides or sulfones.Acylation in the allyl sulfides 11b, d, f and the allyl sulfone 20b takes place at the α-position to the sulfur atom, yielding β,γ-unsaturated ketones.A reductive removal of the sulfide moiety or its conversion into other functional groups was also examined.
- Ohtsuka, Yasuo,Oishi, Takeshi
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p. 443 - 453
(2007/10/02)
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- UMWANDLUNG VON α-AMINOSAEUREN IN α-DIKETONE UEBER OXAZOLINZWISCHENSTUFEN
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A four step sequence for the conversion of α-amino acids into α-diketones under mild conditions is desribed.
- Leyendecker, Joachim,Niewoehner, Ulrich,Steglich, Wolfgang
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p. 2375 - 2378
(2007/10/02)
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