- Synthesis of Enantioenriched α,α-Difluoro-β-arylbutanoic Esters by Pd-Catalyzed Asymmetric Hydrogenation
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Synthesis of optically active gem-difluorinated organic molecules attracts a great deal of interest due to their unique properties in pharmaceutical and agrochemical areas. Herein, a series of enantioenriched α,α-difluoro-β-arylbutanoic esters were prepar
- Dong, Kaiwu,Feng, Sitian,Shen, Chaoren,Tang, Yitian,Yang, Chenjue
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p. 7508 - 7512
(2020/10/09)
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- Oxidative esterification of alcohols and aldehydes using supported iron oxide nanoparticle catalysts
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The synthesis of esters has become an important industrial methodology over the past years because of the role that they serve in the chemical industry. In this study, we present the use of a novel catalyst for the direct conversion of aldehydes into esters. The yields obtained using supported iron oxide nanoparticle catalysts (FeNP) are very high (>90%). The catalyst is also shown to be very stable as shown by the recyclability study (up to 11 times).
- Rajabi, Fatemeh,Arancon, Rick A.D.,Luque, Rafael
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p. 101 - 103
(2015/02/19)
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- Hypervalent iodine(III)-Mediated oxidative decarboxylation of β,γ-unsaturated carboxylic acids
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A novel oxidative decarboxylation of β,γ-unsaturated carboxylic acids mediated by hypervalent iodine(III) reagents is described. The decarboxylative C-O bond forming reaction proceeded in the presence of PhI(OAc)2 to give the corresponding allylic acetates. In addition, decarboxylative C-N bond formation was achieved by utilizing hypervalent iodine(III) reagents containing an I-N bond. Mechanistic studies suggest the unique reactivity of hypervalent iodine reagents in this ionic oxidative decarboxylation.
- Kiyokawa, Kensuke,Yahata, Shunsuke,Kojima, Takumi,Minakata, Satoshi
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supporting information
p. 4646 - 4649
(2015/01/09)
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- Tandem Blaise/retro-Blaise reaction for the nitrile-mediated regioselective intermolecular addition of unstabilized zinc ester enolates (Reformatsky Reagents) to 1-alkynes and 1,3-enynes
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We report the novel use of a nitrile as a mediator to achieve the regioselective intermolecular addition of unstabilized zinc ester enolates (Reformatsky reagents) to 1-alkynes and 1,3-enynes. This reaction is made possible by a reversible addition of enolates to a nitrile (Blaise reaction), generating a zinc aza-enolate that, unlike zinc ester enolates, can add intermolecularly to 1-alkynes and 1,3-enynes. Subsequent removal of the nitrile through a retro-Blaise reaction generates the targeted addition product. This method is combined with a Diels-Alder reaction and subsequent oxidative aromatization, providing a tandem one-pot de novo construction of α-arylated alkanoates from Reformatsky reagents.
- Kim, Ju Hyun,Chun, Yu Sung,Lee, Sang-Gi
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p. 11483 - 11493
(2013/12/04)
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- A novel ketone olefination via organozinc reagents in the presence of diphenyl phosphite
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Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the corresponding olefins. A variety of 1,3-dienes and unsaturated esters were obtained in moderate to excellent yields under mild conditions. The Royal Society of Chemistry 2012.
- Cui, Hua,Li, Ying,Zhang, Songlin
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supporting information
p. 2862 - 2869
(2012/11/07)
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- γ-Selective directed catalytic asymmetric hydroboration of 1,1-disubstituted alkenes
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Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford γ-dioxaborato amides and esters in high enantiomeric purity (90-95% ee). The Royal Society of Chemistry 2012..
- Smith, Sean M.,Hoang, Gia L.,Pal, Rhitankar,Khaled, Mohammad O. Bani,Pelter, Liberty S. W.,Zeng, Xiao Cheng,Takacs, James M.
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supporting information
p. 12180 - 12182
(2013/01/16)
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- Reactions of CF3-substituted boranes with α-diazocarbonyl compounds
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Boranes substituted with a CF3-group can be generated from methyl boronic esters RB(OMe)2 and Me3SiCF3/KF followed by treatment with Me3SiCl. These boranes are stable only in coordinating solvents, and due to the increased Lewis acidity of boron, react rapidly with α-diazocarbonyl compounds to give the products of transfer of the organic group from boron. Alkyl, aryl, vinyl, and alkynyl boronic esters can be used in this reaction.
- Elkin, Pavel K.,Levin, Vitalij V.,Dilman, Alexander D.,Struchkova, Marina I.,Belyakov, Pavel A.,Arkhipov, Dmitry E.,Korlyukov, Alexander A.,Tartakovsky, Vladimir A.
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p. 5259 - 5263
(2011/10/31)
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- Microwave Accelerated Wittig Reactions of Stabilized Phosphorus Ylides with Ketones under Solvent-Free Conditions
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Microwave irradiation accelerates some difficult Wittig reactions of stable phosphorus ylides (e.g. 1) with ketones. Irradiation in a domestic microwave oven of the mixture of reactants, in absence of solvents, allowed to obtain, in shorter times, an impr
- Spinella, Aldo,Fortunati, Tancredi,Soriente, Annunziata
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- Selective formation of alkenes from trimethylsilylmethyl ketones and from acylsilanes
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Trimethylsilylmethyl ketones, readily available from acyl chlorides, undergo a Reformatsky-Peterson reaction sequence to give 3-alkenoates regioselectively.Acylsilanes, however, react with either zinc ester enolates or trimethylsilylmethylmagnesium chloride to give the corresponding tertiary alcohols which, depending on their structure, spontaneously undergo either elimination or a Brook rearrangement-Peterson olefination sequence.These reactions allow the selective formation of vinylsilanes.
- Fuerstner, Alois,Kollegger, Gerlinde,Weidmann, Hans
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p. 295 - 305
(2007/10/02)
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- Reactions of Arylazoxy Aryl Sulfones with α,β-Unsaturated Esters and Nitriles in the Presence of a Palladium(0) Catalyst
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The reactions of arylazoxy aryl sulfones (1) with α,β-unsaturated esters and nitriles in the presence of a palladium(0) catalyst were found to give aryl-substituted esters and nitriles in good yield.
- Kamigata, Nobumasa,Satoh, Mayumi,Fukushima, Takamasa
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p. 2118 - 2120
(2007/10/02)
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- Optimization of asymmetric hydrogenation of 3-phenyl-3-butenoic acid catalyzed by rhodium(I)-4,5-bis-2,2-dimethyldioxolane (DIOP)
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Enantioselective, homogeneous hydrogenation of 3-phenyl-3-butenoic acid (1) has extensively been examined in the presence of the rhodium(I)/4,5-bis-2,2-dimethyldioxolane (DIOP) catalyst systems.Optimization of the reaction conditions was undertaken mainly by controlling effects of added tertiary amines as well as solvent polarities on the enantio-selectivity of the product.The best asymmetric yield (85.1percent e.e.) was attained when the hydrogenation was carried out in the presence of triethylamine (5 molpercent) in 75percent aqueous methanol using a neutral rhodium-DIOP catalyst.
- Yamamoto, Keiji,Ikeda, Kiyoshi,Yin, Leong Kwai
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p. 319 - 332
(2007/10/02)
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- Conversion of α,β-Unsaturated Esters to Their β,γ-Unsaturated Isomers by Photochemical Deconjugation
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It is shown that the α,β-unsaturated esters 1, 2, 4, 5, 6, 16, and 18, which have been reported to be inert to photochemical deconjugation or to undergo the reaction inefficiently, can be converted to their β,γ-unsaturated isomers in good yield if the irradiation is performed in the presence of a catalytic amount of a weak base such as 1,2-dimethylimidazole.It is also shown that addition of catalytic amounts of base can alter the product distribution in cases such as 11, 23, and 26 where more than one isomer can be formed.
- Duhaime, Randy M.,Lombardo, Domenic A.,Skinner, Ian A.,Weedon, Alan C.
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p. 873 - 879
(2007/10/02)
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- Palladium-Catalyzed Decarboxylation-Carbonylation of Allylic Carbonates To Form β,γ-Unsaturated Esters
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Allyl alkyl carbonates undergo a smooth decarboxylation-carbonylation reaction to afford β,γ-unsaturated esters at 50 deg C under atmospheric or low pressure of carbon monoxide and neutral conditions in the presence of palladium-phosphine complexes as catalysts.The reaction offers a very good method for the preparation of β,γ-unsaturated esters from allylic alcohols.
- Tsuji, Jiro,Sato, Koji,Okumoto, Hiroshi
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p. 1341 - 1344
(2007/10/02)
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- PALLADIUM-CATALYZED DECARBOXYLATION-CARBONYLATION OF ALLYLIC CARBONATES TO GIVE β,Γ-UNSATURATED ESTERS UNDER MILD CONDITIONS
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Allylic carbonates undergo facile palladium-catalyzed decarboxylation-carbonylation under mild conditions to give β,γ-unsaturated esters in high yields using palladium-phosphine complex as a catalyst.
- Tsuji, Jiro,Sato, Koji,Okumoto, Hiroshi
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p. 5189 - 5190
(2007/10/02)
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