- Direct Access to α,β-Unsaturated Ketones via Rh/MgCl2-Mediated Acylation of Vinylsilanes
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We report herein the facile and practical construction of α,β-unsaturated ketones via rhodium-catalyzed direct acylation of vinylsilanes with readily available and abundant carboxylic acids. This protocol features access to a diverse array of synthetically useful functionalities with moderate to excellent yields. More importantly, the late-stage functionalization of pharmaceuticals was also realized with synthetically useful yield.
- Chen, Zi-Yan,Deng, Xue-Zu,Song, Yang,Xue, Fei,Yamane, Motoki,Yue, Yan-Ni
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p. 12693 - 12704
(2021/09/28)
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- Enones from Acid Fluorides and Vinyl Triflates by Reductive Nickel Catalysis
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A nickel-catalyzed reductive coupling between acid fluorides and vinyl triflates has been described. This method provides an efficient access to various enones and avoids the requirement for acyl or vinyl metallic reagents in the conventional approaches.
- Pan, Feng-Feng,Guo, Peng,Li, Chun-Ling,Su, Peifeng,Shu, Xing-Zhong
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supporting information
p. 3701 - 3705
(2019/05/24)
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- Ruthenium nitronate complexes as tunable catalysts for olefin metathesis and other transformations
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Novel ruthenium(ii) complexes were obtained as a result of a stoichiometric reaction of Grubbs' benzylidene second generation catalysts with 3-nitropropene. These stable complexes, formally ruthenaisoxazole N-oxide derivatives, display activity in both me
- Wdowik, Tomasz,Samojlowicz, Cezary,Jawiczuk, Magdalena,Malinska, Maura,Wozniak, Krzysztof,Grela, Karol
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supporting information
p. 674 - 676
(2013/02/25)
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- The intramolecular Morita-Baylis-Hillman-type alkylation reaction
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From the initial development of a homologous Morita-Baylis-Hillman reaction utilizing epoxides as electrophiles, the method was expanded to enable the exclusively organocatalyzed intramolecular allylation of enones and to develop the intramolecular MBH-type alkylation of activated alkenes. We successfully utilized both enones and unsaturated thioesters as the activated alkene component. This work, carried out using stoichiometric amounts of the trialkylphosphine, gave an array of functionalized five- and six-membered carbocycles in high yields. With the cycloalkylation of enones and thioesters, conditions that allowed the use of substoichometric amounts of the phosphine catalyst were developed. As a result both five- and six-membered rings can be formed efficiently with little to no loss in yield upon comparison to yields obtained when stoichiometric amounts of trialkylphosphines were employed. We isolated, for the first time, an MBH-type intermediate exhibiting unprecedented trans geometry of the phosphonium salt and acyl group.
- Cran, John W.,Krafft, Marie E.,Seibert, Kimberly A.,Haxell, Thomas F.N.,Wright, James A.,Hirosawa, Chitaru,Abboud, Khalil A.
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p. 9922 - 9943
(2012/02/05)
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- Iron(III)-catalyzed cyclization of alkynyl aldehyde acetals: Experimental and computational studies
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FeCl3·6H2O-and FeBr3-catalyzed Prins cyclization/halogenation of alkynyl aldehyde acetals has been realized with acetyl chloride or bromide as halogen source in dichloromethane to afford 2-(1-halobenzylidene or alkylidene)
- Xu, Tongyu,Yang, Qin,Li, Dongpo,Dong, Jinhua,Yu, Zhengkun,Li, Yuxue
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supporting information; experimental part
p. 9264 - 9272
(2010/10/03)
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- An alternative approach to aldol reactions: Gold-catalyzed formation of boron enolates from alkynes
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A new method for enolate generation via the gold-catalyzed addition of boronic acids to alkynes is reported. The formation of boron enolates from readily accessible ortho-alkynylbenzeneboronic acids proceeds rapidly with 2 mol % PPh3AuNTf2
- Koerner, Cindy,Starkov, Pavel,Sheppard, Tom D.
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supporting information; experimental part
p. 5968 - 5969
(2010/07/05)
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- Indium(III)-catalyzed coupling between alkynes and aldehydes to α,β-unsaturated ketones
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The combined use of a catalytic amount of InX3 (X = OTf and NTf2) and 1-butanol was found to be effective in formal alkynealdehyde metathesis. With this catalytic system, aromatic alkynes reacted with aromatic aldehydes to give chalcones in moderate to good yields. Alkynals were efficiently converted into 5- to 7-membered cyclic compounds by intramolecular alkyne-aldehyde coupling.
- Miura, Katsukiyo,Yamamoto, Kiyomi,Yamanobe, Aya,Ito, Keisuke,Kinoshita, Hidenori,Ichikawa, Junji,Hosomi, Akira
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supporting information; experimental part
p. 766 - 767
(2011/01/09)
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- Cationic P(OPh)3- or PPh3-rhodium(I) complex-catalyzed isomerizations of 5-alkynals to δ-alkynyl ketones, cyclopent-1-enyl ketones, and cyclohexenones
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We have developed catalytic isomerizations of 5-alkynals to γ-alkynyl ketones and cyclopent-1-enyl ketones using [Rh{P(OPh)3} 2]BF4 as a catalyst. Cu(OTf)2 and AgBF 4 are also effective catalysts for
- Tanaka, Ken,Sasaki, Kaori,Takeishi, Kenzo,Hirano, Masao
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p. 5675 - 5685
(2008/09/17)
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- 1,2-Addition of α,α,α-trichlorotoluene to ketones via a Mg Barbier reaction in DMF: New route to cycloalk-1-en-1-yl and alk-1-en-1-yl phenyl ketones
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The reductive cyclocondensation of α,α,α-trichlorotoluene to enolisable ketones enables the preparation of (cyclo)alken-1-en-1-yl phenyl ketones via the formation of an intermediate chlorooxirane. Copyright Taylor & Francis Group, LLC.
- Aaziz, Akima,Oudeyer, Sylvain,Leonel, Eric,Paugam, Jean Paul,Nedelec, Jean-Yves
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p. 1147 - 1154
(2008/02/01)
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- Organocatalysis of the Morita-Baylis-Hillman alkylation using trialkylphosphines
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Using a catalytic amount of trialkylphosphines, alkyl halides undergo efficient intramolecular Morita-Baylis-Hillman cyclization. Georg Thieme Verlag Stuttgart.
- Krafft, Marie E.,Seibert, Kimberly A.
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p. 3334 - 3336
(2008/09/17)
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- Mechanistic implications in the Morita-Baylis-Hillman alkylation: Isolation and characterization of an intermediate
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An intermediate phosphonium salt has never been isolated from the Morita-Baylis-Hillman (MBH) reaction. Due to the weakly basic counterion produced in the MBH alkylation and allylation reactions, the reaction can be stopped after electrophilic attack on t
- Krafft, Marie E.,Haxell, Thomas F. N.,Seibert, Kimberly A.,Abboud, Khalil A.
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p. 4174 - 4175
(2007/10/03)
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- Rhodium-catalyzed acylation of vinylsilanes with acid anhydrides
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A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)2]2, in which the transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key role. The application of this acylation reaction to (1-acyloxyvinyl)silanes provides synthetic methods for α-acyloxy enones, α-diketones, and their derivatives.
- Yamane, Motoki,Uera, Kazuyoshi,Narasaka, Koichi
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p. 477 - 486
(2007/10/03)
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- Unprecedented reactivity in the Morita-Baylis-Hillman reaction; intramolecular α-alkylation of enones using saturated alkyl halides
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sp3 Hybridized electrophiles, never before used in the organo-mediated Morita-Baylis-Hillman reaction, now facilitate the formation of five- and six-membered enone cycloalkylation products. The Royal Society of Chemistry 2005.
- Krafft, Marie E.,Seibert, Kimberly A.,Haxell, Thomas F. N.,Hirosawa, Chitaru
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p. 5772 - 5774
(2007/10/03)
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- Rhodium(I)-catalyzed acylation of alkyne with acylsilane: Transformation of 5- or 6-alkynoylsilane to α-alkylidenecycloalkanone
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Rhodium(I)-catalyzed intramolecular acylation of alkynyl group proceeds by the use of acylsilanes having an alkynyl moiety. 5-and 6-Alkynoylsilanes are converted to α-alkylidenecycloalkanones by treatment with [RhCl(CO)2]2 in the presence of acetic acid via transmetallation between the acylsilane moiety and a rhodium(I) complex.
- Yamane, Motoki,Amemiya, Takuma,Narasaka, Koichi
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p. 1210 - 1211
(2007/10/03)
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- THERAPEUTIC AGENT FOR DIABETES
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A therapeutic agent for diabetes, which comprises a compound of the formula [I] wherein Xis a group of the formula wherein R4and R5are the same or different and each is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, and R6is a hydrogen atom or an amino-protecting group; R1is an optionally substituted alkyl having 1 to 5 carbon atoms, an optionally substituted alkenyl having 2 to 6 carbon atoms and the like, R2is a hydrogen atom, an optionally substituted alkyl having 1 to 5 carbon atoms and the like, R2' is a hydrogen atom, and R3is an optionally substituted alkyl having 1 to 5 carbon atoms and the like, a prodrug thereof, a pharmaceutically acceptable salt thereof, a hydrate thereof and a solvate thereof. The compound of the present invention shows superior blood sugar decreasing action on the state of hyperglycemia, but does not affect the blood sugar when it is in the normal range or in the hypoglycemic state, which means that it is free of serious side effects such as hypoglycemia. Therefore, the compound of the present invention is useful as a therapeutic drug for diabetes and also useful as a preventive of the chronic complications of diabetes.
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- Azo and Azoxy Compounds: XII. Use of Nitrogen Oxide in Organic Synthesis
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Thermal elimination of the alkoxydiazene oxide group from the derivatives of acyl- and benzoylalkanes (cycloalkanes) afforded the corresponding vinyl ketones. Addition of nitrogen oxide and alkoxides to vinyl ketones followed by removal of the acyl group yielded 1,4-dialkoxy-1,2-diazabut-1-ene 2-oxides.
- Yandovskii,Tselinskii
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p. 147 - 152
(2007/10/03)
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- Palladium-Catalyzed Cross-Carbonylation of Aryl Iodides with Five-Membered Cyclic Olefins
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Intermolecular cross-carbonylation of aryl iodides with five-membered cyclic olefins such as dihydrofurans and cyclopentene was found to proceed by using a catalyst system of PdCl2/PPh3 under CO (3-5 atm) in the presence of a tertiary amine.With 2,3- and 2,5-dihydrofurans, 2-aroyl-4,5-dihydro- and 3-aroyl-2,3-dihydrofurans were obtained as the predominant products, respectively, while the reaction of iodobenzene with cyclopentene gave a mixture of three regioisomers of benzoylcyclopentene.The yields of the products were observed to be markedly influenced by the amount of triphenylphosphine added.
- Satoh, Tetsuya,Itaya, Tomoaki,Okuro, Kazumi,Miura, Masahiro,Nomura, Masakatsu
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p. 7267 - 7271
(2007/10/03)
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- Cleavage of Isoxazolines with Tricarbonyltris(acetonitrile)molybdenum and Silica Gel. Synthesis of 1-(2-Oxoalkyl)cyclopropanols from Isoxazoline-5-spirocyclopropanes
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An efficient synthesis of 1-(2-oxoalkyl)cyclopropanols from isoxazoline-5-spirocyclopropanes by selective N-O cleavage effected by Mo(CO)3(MeCN)3 and silica gel is described.
- Guarna, Antonio,Guidi, Antonio,Goti, Andrea,Brandi, Alberto,Sarlo, Francesco De
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p. 175 - 178
(2007/10/02)
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- Cathodic Addition of Benzylidyne Trichloride to Ketones and Aldehydes
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Ketones are converted to homologated enones 7a-g in good yields by cathodic addition of benzylidyne trichloride (1d).As intermediates α-Chlorooxiranes 6 are assumed, which rearrange via α-keto carbenium ions 9 to enones.The intermediacy of 9 is supported by the addition of 1d to norcamphor, where the products indicate equilibrating norbornyl cations as intermediates. α,β-Unsaturated ketones lead depending on steric shielding of the double bond to the cyclopropane 23 as 1,4-adduct or the enone 26 as 1,2-adduct.With aldehydes and 1d, α-chloro or βhydroxy ketones, the conversion products of 2-chlorooxiranes, are obtained.
- Steiniger, Michael,Schaefer, Hans J.
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p. 125 - 132
(2007/10/02)
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- A New, Efficient Approach to α,β-Unsaturated Ketones and β-Hydroxy Ketones From 4,5-Dihydroisoxazoles
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2-(N-Nitrosomethylamino-oxy)ethyl ketones (3), obtained from solvolysis with sodium nitrite of N-methyl-4,5-dihydroisoxazolium methylsulphates (2), were converted into α,β-unsaturated ketones (4) by treatment with base or into β-hydroxy ketones (5) by treatment with carboxylic acids.
- Kwiatkowski, Stefan
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p. 1496 - 1498
(2007/10/02)
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- Synthesis via Isoxazolines, 4. - Base-initiated Ring Opening of 2-Isoxazolines; Synthesis of α-Enoximes and -Enones from Alkenes
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The 2-Isoxazolines 2a-e and 5 undergo ring cleavage on treatment with lithium diisopropylamide (LDA) at -78 --> 0 deg C to afford sterically homogeneous α-enoximes 3a-e and 6. 1H- and 13C-NMR data establish that these compounds have retained the C=N-configuration of the starting isoxazoline.Subsequent deoximation by acidic TiCl3 solution in DMF yields the α-enones 4a-e and the tetrahydropyran 7, respectively.This constitutes a new, regioselective sequence (1 --> 4) for the acylation of alkenes, which avoids cationic intermediates.Studies to determine the mechanistic course and the scope of the ring cleavage reaction show that endo and/or exo anions are formed first, depending on the substitution pattern.The former may isomerize ( -78 deg C) to produce enoximates; both offer the possibility to prepare new 4- or 3α-substituted isoxazolines by the reaction with electrophiles as demonstrated by two examples (2f, 2h).
- Grund, Hartmut,Jaeger, Volker
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