- Mizoroki-Heck Reaction of Unstrained Aryl Ketones via Ligand-Promoted C-C Bond Olefination
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Mizoroki-Heck reaction of unstrained aryl ketone with acrylate/styrene is accomplished via palladium-catalyzed ligand-promoted C-C bond cleavage. Various (hetero)aryl ketones are compatible in the reaction, affording the alkene product in good to excellent yields. Further applications in the late-stage olefination of some drugs, natural products, and fragrance-derived aryl ketones demonstrate the synthetic utility of this protocol. By employing ketone as both the directing group and the leaving group, 1,2-bifunctionalization is achieved via sequential ortho-C-H alkylation/ipso-Heck olefination.
- Wang, Mei-Ling,Xu, Hui,Li, Han-Yuan,Ma, Biao,Wang, Zhen-Yu,Wang, Xing,Dai, Hui-Xiong
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p. 2147 - 2152
(2021/04/05)
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- Pd-catalyzed oxidative Heck-type arylation of vinyl ketones, alkenes, and acrylates with Sb-aryl-tetrahydrodibenz[c,f][1,5]azastibocines
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The Pd-catalyzed cross-coupling reactions of Sb-aryl-1,5-azastibocines with alkenes are described. The reactions of azastibocines with alkenes such as vinyl ketones, alkenes, and acrylates in the presence of 10 mol% PdCl2 at 80 °C in DMA under aerobic conditions produced Heck adducts in moderate-to-excellent yields. Single-crystal X-ray and NMR analysis revealed that the aryl donors in this reaction, the Sb-aryl-1,5-azastibocines, are hypervalent compounds that display N–Sb intramolecular non-bonding interaction. These are the first examples of Pd-catalyzed Heck-type arylations using heterocyclic hypervalent organoantimony compounds. Although the reactions proceeded efficiently with the azastibocines, they hardly progressed with trivalent and pentavalent triarylantimony reagents.
- Murata, Yuki,Kakusawa, Naoki,Arakawa, Yukako,Hayashi, Yukako,Morinaga, Shun,Ueda, Masaaki,Hyodo, Tadashi,Matsumura, Mio,Yamaguchi, Kentaro,Kurita, Jyoji,Yasuike, Shuji
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- Novel antiobesity agents: Synthesis and pharmacological evaluation of analogues of Rimonabant and of LH21
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Searching for novel antiobesity agents, a series of cannabinoid LH21 and of Rimonabant-fatty acid amide analogues have been prepared. Synthesis of pyrazoles 2a-2c was achieved by a two steps simple methodology via α,β-unsaturated ketones. Carboxamides 8a-8h were obtained in good yields from esters 7a-7c by a one-pot procedure which takes place under mild conditions. New compounds have been evaluated in vivo as anorectic agents. Some of them showed interesting properties reducing food intake in rats by a mechanism which does not involve the endocannabinoid system.
- Alvarado, Mario,Decara, Juan,Luque, María Jesús,Hernandez-Folgado, Laura,Gómez-Ca?as, María,Gómez-Ruiz, María,Fernández-Ruiz, Javier,Elguero, José,Jagerovic, Nadine,Serrano, Antonia,Goya, Pilar,De Fonseca, Fernando Rodríguez
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p. 1708 - 1716
(2013/05/09)
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- Palladium-catalysed heck reactions of alk-1-en-3-ones with aryl bromides: A very simple access to (E)-1-arylalk-1-en-3-ones
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When appropriate reaction conditions are used, very high yields of (E)-1-arylalk-1-en-3-one derivatives can be obtained by palladium-catalysed reactions of alk-1-en-3-ones with aryl bromides. The tetraphosphine cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl) cyclopentane in combination with [Pd(C3H5)Cl]2 was found to be a very efficient catalyst for this reaction. In general, higher reaction rates were observed with electron-poor aryl bromides, but the electron-rich aryl bromides 1-bromo-4-(dimethylamino)benzene and 4-bromoanisole also led to the arylated enones in high yields. Even with sterically very congested aryl bromides such as 9-bromoanthracene, 1-bromo-2,4,6-trimethylbenzene or 1-bromo-2,4,6-triisopropylbenzene, the expected (E)-1-arylalk-1-en-3-ones were obtained in moderate to good yields. These enones appear to be unstable under the reaction conditions, and the addition of a small amount of hydroquinone to the reaction mixture was found to be crucial, especially for the vinylation of electron-deficient aryl bromides. A variety of alk-1-en-3-ones has been employed, and better results in terms of substrate/ catalyst ratios were obtained when oct-1-en-3-one or hex-1-en-3-one was used than when but-1-en-3-one or pent-1-en-3-one was used. It should be noted that several reactions can be performed with as little as 0.1-0.001 mol% catalyst. Georg Thieme Verlag Stuttgart.
- Lemhadri, Mhamed,Fall, Yacoub,Doucet, Henri,Santelli, Maurice
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experimental part
p. 1021 - 1035
(2009/12/02)
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- Recyclable gold nanoparticle catalyst for the aerobic alcohol oxidation and C-C bond forming reaction between primary alcohols and ketones under ambient conditions
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A recyclable gold catalyst is synthesized from readily available reagents by immobilizing gold nanoparticles in aluminum oxyhydroxide support through a simple sol-gel method. The catalyst showed the high activity even at room temperature in the aerobic oxidation of various alcohols and in the coupling reaction between primary alcohols and ketones.
- Kim, Sungjin,Bae, Sang Won,Lee, Jae Sung,Park, Jaiwook
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experimental part
p. 1461 - 1466
(2009/04/11)
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- Gold(III)-catalyzed direct nucleophilic substitution of propargylic alcohols
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Gold-catalyzed nucleophilic substitution of propargylic alcohols with various nucleophiles (allylsilane, electron-rich aromatics, alcohols, thiols, hydrides, 1,3-dicarbonyl derivatives, sulfonamides) is described under very mild conditions (room temperatu
- Georgy, Marie,Boucard, Valérie,Debleds, Olivier,Zotto, Christophe Dal,Campagne, Jean-Marc
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experimental part
p. 1758 - 1766
(2009/06/28)
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- One single catalyst, Pd(OAc)2, for two sequential very different steps: Allylic alcohol oxidation-Heck reaction. Access to functionalised α,β-unsaturated ketones
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A single addition of the catalyst, Pd(OAc)2, was realised to mediate two transformations as different as allylic alcohol oxidation under O2 and C-C bond formation of the Heck type, to give substituted α,β-unsaturated ketones without intermediate purification. The Royal Society of Chemistry.
- Batt, Frederic,Gozzi, Christel,Fache, Fabienne
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supporting information; experimental part
p. 5830 - 5832
(2009/04/13)
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- Palladium-catalyzed Heck arylations of allyl alcohols in ionic liquids: Remarkable base effect on the selectivity
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Pd-catalyzed Heck arylation of allyl alcohols in tetraalkylammonium ionic liquids (ILs) can be made highly selective toward the formation of either aromatic carbonyl compounds or aromatic conjugated alcohols by carefully choosing both the IL and the base.
- Calo, Vincenzo,Nacci, Angelo,Monopoli, Antonio,Ferola, Valentina
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p. 2596 - 2601
(2007/10/03)
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- Stereoselective functionalization of β-iodo-α,β-unsaturated ketones via an iodine-copper exchange reaction
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β-Iodo-α,β-unsaturated carbonyl compounds undergo a stereoselective iodine-copper exchange reaction with (Nphyl)2CuLi, providing the corresponding alkenyl cuprates with retention of the double bond configuration. No competitive addition/elimina
- Yang, Xiaoyin,Knochel, Paul
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p. 1941 - 1943
(2007/10/03)
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- Recyclable palladium catalyst for highly selective α alkylation of ketones with alcohols
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(Chemical Equation Presented) An air-stable, heterogeneous, and recyclable catalyst composed of palladium nanoparticles entrapped in aluminum hydroxide was applied to a highly selective α alkylation. A wide range of aliphatic and aromatic ketones and primary alcohols were coupled to prepare enones in an O2 atmosphere and ketones in an argon atmosphere (see scheme).
- Kwon, Min Serk,Kim, Namdu,Seo, Seong Hyeok,Park, In Soo,Cheedrala, Ravi Kumar,Park, Jaiwook
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p. 6913 - 6915
(2007/10/03)
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- Gold(III)-catalyzed nucleophilic substitution of propargylic alcohols
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Gold-catalyzed nucleophilic substitution on propargylic alcohols, with various C-, O-, and S-nucleophiles, is described under very mild conditions (room temperature, dichloromethane) in 0-97% yield. Copyright
- Georgy, Marie,Boucard, Valerie,Campagne, Jean-Marc
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p. 14180 - 14181
(2007/10/03)
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- Strong Bicyclic Guanidine Base-promoted Wittig and Horner-Wadsworth-Emmons Reactions
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formula presented A convenient procedure to effect the Wittig and Horner-Wadsworth-Emmons reactions employs guanidine TBD and MTBD as base-promoters; mild reaction conditions, high efficiency, and facile isolation of the final products make the present methodology, at least in some cases, a practical alternative to known procedures.
- Simoni, Daniele,Rossi, Marcello,Rondanin, Riccardo,Mazzali, Angelica,Baruchello, Riccardo,Malagutti, Cinzia,Roberti, Marinella,Invidiata, Francesco Paolo
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p. 3765 - 3768
(2007/10/03)
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- Benzotriazole- and 1,2,4-triazole-stabilized allylic anions: Applications in syntheses of functionalized α,β-unsaturated ketones, γ-lactones, γ-lactams, and β-substituted esters
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Deprotonated 1-(benzotriazol-1-yl)-1-ethoxy-2-hexene (7) reacted with alkyl halides, aldehydes, ketones, imines, and α,β-unsaturated esters to give exclusively the α-alkylated products 8a-c, 10a,b, 12, 14, 16, and 18a,b, respectively. Without isolation, these products were hydrolyzed under mild conditions to generate the corresponding simple or functionalized α,β-unsaturated ketenes 9a-c, 11a,b, 13, 15, 17, and 19a,b. Similar reactions with the phenyl-substituted analog 3-(benzotriazol-1-yl)-3-ethoxy-1-phenyl-1-propene (21) also gave the analogous α-products, but they were accompanied by small amounts of the γ-products in most cases. By contrast, deprotonation of the corresponding triazole derivative 29 with butyllithium followed by reactions with alkyl halides, aldehydes, ketones, or imines yielded exclusively γ-alkylated adducts 32, 34, 36, 38, 40, and 42. Intermediates 32, 34, 36, 38, 40, and 42 were readily converted into β-substituted esters 33a-c, γ-lactones 35a,b, 39, 41, and 43, and γ-lactams 37a-c on hydrolysis.
- Katritzky,Feng,Lang
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p. 706 - 714
(2007/10/03)
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- Ring-opening of isoxazolidine nucleus: Competitive formation of α,β-enones and tetrahydro-1,3-oxazines
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Treatment of isoxazolidine derivatives with methyl iodide, followed by simple heating with aqueous NaOH, gives rise to a competitive formation of α,β-enones and tetrahydro-1,3-oxazines. The ring-opening process is controlled by the stereochemistry of H5 which represents the driving factor of two competitive reaction routes.
- Casuscelli, Franco,Chiacchio, Ugo,Rescifina, Antonio,Romeo, Roberto,Romeo, Giovanni,Tommasini, Silvana,Uccella, Nicola
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p. 2979 - 2990
(2007/10/02)
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- Synthesis of α,β-Unsaturated Carbonyl Compounds by Titanium Tetraalkoxide-Induced Aldol Condensation under Neutral Conditions
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Aldehydes and ketones, when treated with titanium tetraalkoxides in a hydrocarbon solvent at 20-140 deg C, undergo aldol condensation to give α,β-unsaturated carbonyl compounds.To avoid Meerwein-Ponndorf-Verley type reduction of the carbonyl compounds, titanium tetra-tert-butoxide is used, if the reaction is carried out at higher temperatures.In all other cases titanium tetraisopropoxide can be successfully employed.The outlined procedure offers the possibility of performing aldol condensations under neutral conditions.
- Mahrwald, Rainer,Schick, Hans
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p. 592 - 595
(2007/10/02)
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- β-HALOVINYL KETONES: SYNTHESIS FROM ACETYLENIC KETONES
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The reaction of terminal acetylenic ketones with NaI or LiBr gave almost exclusively E-β-iodo-or E-β-bromovinyl ketones in trifluoracetic acid, while Z-β-iodo or Z-β-bromovinyl ketones were the major products in acetic acid.Trimethylsilyl iodide and bromide reacted smoothly with acetylenic ketones at -78 deg C to give TMS-allenolates which were readily converted to β-iodo and β-bromovinyl ketones, respectively.
- Taniguchi, Mikio,Kobayashi, Shozo,Nakagawa, Masako,Hino, Tohru,Kishi, Yoshito
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p. 4763 - 4766
(2007/10/02)
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- N,O-HETEROCYCLICS-14 CONVERSION OF ISOXAZOLIDINES INTO α,β-ENONES
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Substituted isoxazolidines formed by 1,3-dipolar cycloaddition of nitrones to alkenes undergo ring-opening elimination to α,β-enones when treated with trimethyl phosphate.The reaction involves initial alkylation giving the isoxazolidinium intermediate which collapses to the α,β-enone by a Hofmann-like elimination having an orientation controlled by electronic factors, the first step being rate-determining.
- Liguori, Angelo,Sindona, Giovanni,Uccela, Nicola
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p. 1901 - 1906
(2007/10/02)
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- N,O-HETEROCYCLES. XVI. DIRECT CONVERSION OF SOME ISOXAZOLIDINES INTO ALCOHOLS VIA α,β-ENONES
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The 1,3-dipolar cycloadducts between nitrones and alkenes are converted into alcoholic derivatives by trimethyl phosphate and by subsequent reduction.The reaction of the substituted isoxazolidines, exempt of further functionalities, proceeds under the action of TMP through a sequence of steps including a Hofmann-like elimination with electronic-controlled orientation indicated also by thermochemical calculations.The overall process leads to the formation of saturated and unsaturated alcohols as known for the reduction step.
- Liguori, Angelo,Sindona, Giovanni,Uccella, Nicola
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p. 369 - 374
(2007/10/02)
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- A REGIOSELECTIVE ENOLATE FORMATION OF TRIMETHYLSILYLMETHYL KETONES APPLICATION TO THE (E)-SELECTIVE SYNTHESIS OF α,β-UNSATURATED KETONES
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Two possible enolate anions of trimethylsilylmethyl ketones have been prepared regioselectively by the appropriate choice of base.The one directed to the silylmethyl site behaves as a highly reactive and (E)-selective condensation reagent to aldehydes.
- Matsuda, Isamu,Okada, Hisashi,Sato, Susumo,Izumi,Yusuke
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p. 3879 - 3882
(2007/10/02)
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- Mercury in Organic Chemistry. 25. Rhodium(I)-Catalyzed Alkenylation of Arylmercurials
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Arylmercurials and vinyl halides are catalytically cross-coupled to aryl olefins in fair to good yields by 10percent ClRh(PPh3)3.This reaction appears to proceed through an arylvinylrhodium(III) intermediate.
- Larock, R. C.,Narayanan, K.,Hershberger, S. S.
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p. 4377 - 4380
(2007/10/02)
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