28918-08-3Relevant articles and documents
Neutral-eosin Y-catalyzed regioselective hydroacylation of aryl alkenes under visible-light irradiation
Liu, Haiwang,Xue, Fei,Wang, Mu,Tang, Xinxin,Wu, Jie
supporting information, p. 406 - 410 (2020/12/30)
Styrene derivatives were hydroacylated with exclusive anti-Markovnikov selectivity by using neutral eosin Y as a direct hydrogen-atom-transfer (HAT) catalyst under visible-light irradiation. Aldehydes and styrenes with various substituents were tolerated (>20 examples), giving the corresponding products in moderate to high yields. The key acyl radical intermediate was generated from a direct HAT process induced by photoexcited eosin Y. Subsequent addition to styrenes and a reverse HAT process generated the ketone products.
α-Arylation of Carbonyl Compounds through Oxidative C?C Bond Activation
Li, Jing,Bauer, Adriano,Di Mauro, Giovanni,Maulide, Nuno
supporting information, p. 9816 - 9819 (2019/06/25)
A synthetically useful approach for the direct α-arylation of carbonyl compounds through a novel oxidative C?C bond activation is reported. This mechanistically unusual process relies on a 1,2-aryl shift and results in all-carbon quaternary centers. The transformation displays broad functional-group tolerance and can in principle also be applied as an asymmetric variant.
Reductive Reformatsky-Honda reaction of α,β-unsaturated esters: Facile formation of 1,3-dicarbonyl compounds and β-hydroxy esters
Sato, Kazuyuki,Isoda, Motoyuki,Ohata, Shizuka,Morita, Shuhei,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
supporting information; scheme or table, p. 510 - 514 (2012/04/23)
The reaction of tris(triphenylphosphine)rhodium chloride [RhCl(PPh 3)3] with diethylzinc (Et2Zn) easily afforded a rhodium-hydride complex that effects the 1,4-reduction of α,β- unsaturated esters to give rhodium enolates. Formation of the rhodium enolate is followed by transmetalation with the zinc species to give a Reformatsky-type reagent, and this reacts with various acid chlorides at the α-position to give β-keto esters. The Reformatsky-type reagent also reacts with various electrophiles such as aldehydes, ketones and acid anhydrides to give the corresponding products in which the electrophiles were introduced reductively at the α-position of α,β-unsaturated esters. Copyright
Iridium-catalyzed reaction of enones with alcohols affording 1,3-diketones
Obora, Yasushi,Nakamura, Kazuhiro,Hatanaka, Shintaro
supporting information; experimental part, p. 6720 - 6722 (2012/07/17)
An iridium-catalyzed coupling reaction of alcohols with enones has been successfully developed providing access to 1,3-diketones with high selectivity in good yields. This reaction provides an atom-economical route to 1,3-diketones from readily available
Amberlyst-15 in ionic liquid: an efficient and recyclable reagent for the benzylation and hydroalkylation of β-dicarbonyl compounds
Qureshi, Ziyauddin S.,Deshmukh, Krishna M.,Tambade, Pawan J.,Bhanage, Bhalchandra M.
scheme or table, p. 724 - 729 (2010/04/05)
Benzylation and hydroalkylation of 1,3-dicarbonyl compounds using Amberlyst-15 immobilized in ionic liquid [Bmim][PF6] as an efficient reusable reagent was studied. The reagent was compared with other solid acid reagents along with role of the ionic liquid. The effect of various reaction parameters like type of reagent, solvent, substrate molar ratio, reaction time, and temperature were studied. Present protocol is advantageous due to the ease in handling of reagent, simple work-up procedure, economical and environmentally benign process. The products were obtained in good to excellent yield and applicable to wide variety of substrates.
Direct synthesis of 1,3-diketones by Rh-catalyzed reductive α-acylation of enones
Sato, Kazuyuki,Yamazoe, Satoshi,Yamamoto, Rie,Ohata, Shizuka,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
supporting information; experimental part, p. 2405 - 2408 (2009/05/11)
(Chemical Equation Presented) 1,3-Diketones were synthesized from α,β-unsaturated ketones by treatment with acid chlorides and Et 2Zn in the presence of RhCl(PPh3)3. This is a very simple and extremely chemoselective reaction to give the adduct at the α-position of α,β-unsaturated ketones.
Ionic liquid as catalyst and solvent: the remarkable effect of a basic ionic liquid, [bmIm]OH on Michael addition and alkylation of active methylene compounds
Ranu, Brindaban C.,Banerjee, Subhash,Jana, Ranjan
, p. 776 - 782 (2007/10/03)
A basic ionic liquid, 1-methyl-3-butylimidazolium hydroxide, [bmIm]OH, catalyzes the Michael addition of active methylene compounds to conjugated ketones, carboxylic esters and nitriles. It further catalyzes the addition of thiols to α,β-acetylenic ketones and alkylation of 1,3-dicarbonyl and -dicyano compounds. The Michael addition to α,β-unsaturated ketones proceeds in the usual way, giving the monoaddition products, whereas addition to α,β-unsaturated esters and nitriles leads exclusively to the bis-addition products. The α,β-acetylenic ketones undergo double conjugate addition with thiols producing β-keto 1,3-dithio-derivatives. In the alkylation reaction the acyclic 1,3-diketones are monoalkylated, whereas cyclic ketones undergo dialkylation under identical conditions. All these reactions were carried out without any organic solvent. The ionic liquid can also be recycled.
Efficient metal-catalyzed direct benzylation and allylic alkylation of 2,4-pentanediones
Rueping, Magnus,Nachtsheim, Boris J.,Kuenkel, Alexander
, p. 825 - 828 (2007/10/03)
(Chemical Equation Presented) A highly effective metal-catalyzed benzylation and allylic alkylation of 2,4-pentanediones has been developed. This new bismuth-catalyzed direct carbon-carbon bond forming reaction provides the corresponding monoalkylated dicarbonyl compounds in high yields after short reaction times using the lowest amounts of catalyst (1 mol %) and the free alcohol. In addition, a new route to substituted indenes is presented.
Nucleophilic substitution reactions of alcohols with use of montmorillonite catalysts as solid Bronsted acids
Motokura, Ken,Nakagiri, Nobuaki,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
, p. 6006 - 6015 (2008/02/10)
(Chemical Equation Presented) We have developed an environmentally benign synthetic approach to nucleophilic substitution reactions of alcohols that minimizes or eliminates the formation of byproducts, resulting in a highly atom-efficient chemical process. Proton- and metal-exchanged montmorillonites (H- and Mn+-mont) were prepared easily by treating Na +-mont with an aqueous solution of hydrogen chloride or metal salt, respectively. The H-mont possessed outstanding catalytic activity for nucleophilic substitution reactions of a variety of alcohols with anilines, because the unique acidity of the H-mont catalyst effectively prevents the neutralization by the basic anilines. In addition, amides, indoles, 1,3-dicarbonyl compounds, and allylsilane act as nucleophiles for the H-mont-catalyzed substitutions of alcohols, which allowed efficient formation of various C-N and C-C bonds. The solid H-mont was reusable without any appreciable loss in its catalytic activity and selectivity. Especially, an Al3+-mont showed high catalytic activity for the α-benzylation of 1,3-dicarbonyl compounds with primary alcohols due to cooperative catalysis between a protonic acid site and a Lewis acidic Al3+ species in its interlayer spaces.
Direct Photolysis and Electron Transfer Photooxygenation of Enol Acetates of 3-Phenylpropiophenones
Algarra, Felipe,Baldovi, Maria V.,Garcia, Hermenegildo,Miranda, Miguel A.,Primo, Jaime
, p. 209 - 216 (2007/10/02)
Direct photolysis of enol acetates of 3-phenylpropiophenones 1a-c gives rise to the parent propiophenones 2a-c and the 1,3-acyl shift products 3a-c.By contrast, 2,4,6-triphenylpyrylium tetrafluoroborate sensitized photolysis of substrates 1a-c affords the α-acetyloxypropiophenones 7a-c as the most general products.These results have been rationalized according to the generation of radical pairs in the direct photolysis and radical cations in the photoinduced electron transfer processes. Keywords.Enol acetates of 3-phenylpropiophenones; 1,3-Acyl migration; Photoinduced electron transfer; 2,4,6-triphenylpyrylium tetrafluoroborate.
