- Asymmetric Umpolung Hydrogenation and Deuteration of Alkenes Catalyzed by Nickel
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Nickel-catalyzed asymmetric hydrogenation of several types of alkenes proceeds in high enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, n
- Guo, Siyu,Wang, Xiuhua,Zhou, Jianrong Steve
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supporting information
p. 1204 - 1207
(2020/02/04)
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- Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform
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Arylboronic acids react with aldehydes and α,β-unsaturated carbonyl compounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform is essential for this reaction, these reactions would be promoted by dichloromethylpalladium(II) species.
- Yamamoto, Tetsuya,Iizuka, Michiko,Takenaka, Hiroto,Ohta, Tetsuo,Ito, Yoshihiko
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experimental part
p. 1325 - 1332
(2009/09/28)
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- Ruthenium-catalyzed 1,4-addition of organoboronic acids to α,β-unsaturated ketones
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A ruthenium-catalyzed 1,4-addition of organoboronic acids to α,β-unsaturated ketones has been developed. The use of 2-(di-tert-butylphosphino)biphenyl as the ligand in combination with [RuCl 2(p-cymene)]2 complex catalyzes these reactions to selectively give 1,4-adducts in good yield by effectively suppressing Heck-type and reduced products. Copyright
- Shintani, Ryo,Hayashi, Tamio
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p. 724 - 725
(2008/12/21)
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- Asymmetric conjugate reduction of α,β-unsaturated ketones and esters with chiral rhodium(2,6-bisoxazolinylphenyl) catalysts
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New asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2- one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60°C in 95% ee and 98 % ee, respectively, by 1 mol % of catalyst loading. (EtO) 2MeSiH proved to be the best hydrogen donor of choice. tert-Butyl (E)-β-methylcinnamate and β-isopropylcinnamate could also be reduced to the corresponding dihydrocinnamate derivatives up to 98% ee.
- Kanazawa, Yoshinori,Tsuchiya, Yasunori,Kobayashi, Kazuki,Shiomi, Takushi,Itoh, Jun-Ichi,Kikuchi, Makoto,Yamamoto, Yoshihiko,Nishiyama, Hisao
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- Palladium catalyzed conjugate 1,4-addition of organoboronic acids to α,β-unsaturated ketones
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1,4-Addition of arylboronic acids to α,β-unsaturated ketones was smoothly catalyzed by palladium(0) phosphine complexes with chloroform in the presence of base. It is remarked that the palladium(0) complexes have no catalytic activity in the absence of chloroform. The reaction proceeded without β-hydride elimination. Copyright
- Yamamoto, Tetsuya,Iizuka, Michiko,Ohta, Tetsuo,Ito, Yoshihiko
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p. 198 - 199
(2007/10/03)
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- Rhodium catalyzed conjugated addition of unsaturated carbonyl compounds by triphenylbismuth in aqueous media and under an air atmosphere
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In the presence of a rhodium catalyst, α,β-unsaturated esters and ketones react with triphenylbismuth in aqueous media and under an air atmosphere to give the corresponding conjugated addition products in high yields.
- Venkatraman, Sripathy,Li, Chao-Jun
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p. 781 - 784
(2007/10/03)
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- The utilization of supercritical carbon dioxide in the palladium- catalyzed hydroarylation of β-substituted-α,β-enones
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The utilization of supercritical carbon dioxide (scCO2) has a beneficial effect on the palladium-catalyzed reaction of acyclic β- substituted-α,β-enones with aryl iodides and hydroarylation (formal conjugate addition) products were isolated in good to high yields. The hydroarylation to vinylic substitution ratio is usually high.
- Cacchi, Sandro,Fabrizi, Giancarlo,Gasparrini, Francesco,Pace, Paola,Villani, Claudio
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p. 650 - 652
(2007/10/03)
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- SYNTHESIS OF JUVABIONE ANALOGUES
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Alkylation of various β-ketoesters IIIa-d with bis(p-methoxycarbonylphenyl)bromomethane (II) and bis(p-chlorophenyl)bromomethane (VI) followed by cleavage of ethoxycarbonyl group or hydrolysis and esterification gave methoxycarbonylphenyl and chlorophenyl analogues of ar-juvabione, respectively.Condensation of bis(p-methoxycarbonylphenyl)methanol (IX) with isovaleryl and trichloroacetyl chloride gave isovalerate X and trichloroacetate XI, respectively, while the condensation of bis(p-chlorophenyl)methanol (XII) with isovaleryl chloride and citronellyl bromide yieldedisovalerate XIII and citronellyl ether XIV, respectively.The methoxycarbonylation of aryl-alkyl ketones XVa-d with oxalyl chloride and treatment with methanol furnished various ar-juvabione analogues XVIa-d.The compounds Vb, Vc, Vd, XVIb, and XVIc showed high activity against Dysdercus koenigii at 1μg concentration.
- Mane, Ramchandra B.,Desai, Uday V.,Hebbalkar, Geeta D.
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p. 646 - 657
(2007/10/02)
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- CONJUGATE ADDITION OF ORGANOCOPPER REAGENTS TO N-TOSYLATED α, β-UNSATURATED AMIDES
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N-Tosylated α, β-unsaturated amides and lactams undergo facile conjugate addition with R2CuLi or RMgX/CuI (cat.).Stereoselective synthesis of trans-β,γ-dialkyl-γ-lactams can be achieved by this procedure.The resulting N-tosylamide moiety is further transformed to alcohol and several carbonyl compounds by way of reduction or nucleophillic displacement.
- Nagashima, Hideo,Ozaki, Nobuyasu,Washiyama, Masayoshi,Itoh, Kenji
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p. 657 - 660
(2007/10/02)
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