- Enantiospecific C-H Activation Using Ruthenium Nanocatalysts
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The activation of C-H bonds has revolutionized modern synthetic chemistry. However, no general strategy for enantiospecific C-H activation has been developed to date. We herein report an enantiospecific C-H activation reaction followed by deuterium incorporation at stereogenic centers. Mechanistic studies suggest that the selectivity for the α-position of the directing heteroatom results from a four-membered dimetallacycle as the key intermediate. This work paves the way to novel molecular chemistry on nanoparticles.
- Taglang, Céline,Martínez-Prieto, Luis Miguel,Del Rosal, Iker,Maron, Laurent,Poteau, Romuald,Philippot, Karine,Chaudret, Bruno,Perato, Serge,Sam Lone, Ana?s,Puente, Céline,Dugave, Christophe,Rousseau, Bernard,Pieters, Grégory
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supporting information
p. 10474 - 10477
(2015/09/02)
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- Microwave-Enhanced Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)imines
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Microwave irradiation has considerably enhanced the efficiency of the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)imines in isopropyl alcohol catalyzed by a ruthenium complex bearing the achiral ligand 2-amino-2-methylpropan-1-ol. In addition to shortening reaction times for the transfer hydrogenation processes to only 30 min, the amounts of ruthenium catalyst and isopropyl alcohol can be considerably reduced in comparison with our previous procedure assisted by conventional heating, which diminishes the environmental impact of this new protocol. This methodology can be applied to aromatic, heteroaromatic and aliphatic N-(tert-butylsulfinyl)ketimines, leading, after desulfinylation, to the expected primary amines in excellent yields and with enantiomeric excesses of up to 96 %. Microwave irradiation promotes the asymmetric transfer hydrogenation of N-(tert-butylsulfinyl)imines in 2-propanol catalysed by a ruthenium complex bearing an achiral β-amino alcohol as ligand. After desulfinylation, α-branched primary amines containing aromatic, heteroaromatic and aliphatic substituents are obtained in excellent yields and with enantiomeric excesses of up to 96 %.
- Pablo, Oscar,Guijarro, David,Yus, Miguel
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p. 7034 - 7038
(2016/02/19)
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- A versatile Ru catalyst for the asymmetric transfer hydrogenation of both aromatic and aliphatic sulfinylimines
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A highly efficient Ru catalyst based on an achiral, very simple, and inexpensive amino alcohol ligand (2-amino-2-methylpropan-1-ol) has been developed for the asymmetric transfer hydrogenation (ATH) of chiral N-(tert-butylsulfinyl)imines. This complex is able to catalyze the ATH of both aromatic and the most challenging aliphatic sulfinylimines by using isopropyl alcohol as the hydrogen source. The diastereoselective reduction of aromatic, heteroaromatic, and aliphatic sulfinylketimines, including sterically congested cases, over short reaction times (1-4 h), followed by desulfinylation of the nitrogen atom, affords the corresponding highly enantiomerically enriched (ee up to >99%) α-branched primary amines in excellent yields. The same ligand was equally effective for the synthesis of both (R)- and (S)-amines by using the appropriate absolute configuration in the iminic substrate. DFT mechanistic studies show that the hydrogen-transfer process is stepwise. Moreover, the origin of the diastereoselectivity has been rationalized.
- Pablo, Oscar,Guijarro, David,Kovacs, Gabor,Lledos, Agusti,Ujaque, Gregori,Yus, Miguel
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supporting information; experimental part
p. 1969 - 1983
(2012/03/26)
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- A one-pot asymmetric sequential animation-alkylation of aldehydes: Expedient synthesis of aliphatic chiral amines
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A one-pot asymmetric sequential amination-alkylation method has been developed for the synthesis of alkyl-alkyl′ α-chiral primary amines (aliphatic primary amines with a chiral center adjacent to the nitrogen atom) from aldehydes. In situ aldimine formati
- Wakchaure, Vijay N.,Mohanty, Rashmi R.,Shaikh, Ahson J.,Nugent, Thomas C.
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p. 959 - 964
(2008/02/13)
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- SULPHONAMIDOANILINE DERIVATIVES BEING JANUS KINASES INHIBITORS
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The invention relates to sulphonamidoanilines of formula (I) wherein A is N or CH, W, X, Y and Z are N or CH under the proviso that at least one of the three symbols W, X and Y represent CH, R1 represents NR4R5 or OR4
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Page/Page column 31
(2010/11/27)
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- Selective diethylzinc reduction of imines in the presence of ketones catalyzed by Ni(acac)2
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(Chemical Equation Presented) A selective reduction method of an electronically deficient imine in the presence of ketone was developed by employing Et2Zn and 5 mol % of Ni(acac)2. The method was applied in the reduction of SS-tert-butanesulfinyl ketimines 1 to afford amines 2 in 23-92% yields and 73:27 to 98:2 diastereoselectivities. A plausible mechanism was proposed on the basis of an NMR study.
- Xiao, Xue,Wang, Haowei,Huang, Zhiyan,Yang, Jun,Bian, Xiaoxia,Qin, Yong
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p. 139 - 142
(2007/10/03)
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- Asymmetric synthesis of chiral amines by highly diastereoselective 1,2- additions of organometallic reagents to N-tert-butanesulfinyl imines
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High yielding and highly diastereoselective methods for 1,2-additions of organometallic reagents to N-tert-butanesulfinyl aldimines (2) and N-tert- butanesulfinyl kerimines (3) are described. The additions of alkyl, aryl, alkenyl, and allyl carbanions to a diverse set of imines with different steric and electronic properties are demonstrated. Acidic methanolysis of the sulfinamide products (4 and 6) delivers highly enantioenriched α-branched and α,α-dibranched amines. Since a broad range of sulfinyl imines are easily accessible from aldehydes and ketones, a wide variety of enantioentriched amines may be prepared.
- Cogan, Derek A.,Liu, Guangcheng,Ellman, Jonathan
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p. 8883 - 8904
(2007/10/03)
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- Synthesis of enantiopure primary amines by stereoselective ring opening of chiral octahydro-1,3-benzoxazines by Grignard and organoaluminum reagents
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Chiral 1,3-perhydrobenzoxazines 1, 2, and 9-14, prepared by condensation of 8-(benzylamino)-menthol with different aldehydes, react with alkylmagnesium bromides and trimethylaluminum leading to the open amino alcohols 3a-d, 4a-d, and 15-20 in excellent chemical yields and good to excellent diastereomeric excess. The sequential elimination of the menthol appendage by heating with P2O5 and the benzyl group by hydrogenolysis lead to primary amines 7a-d, 8a-d, and 27-30 in excellent chemical yields and ee. The addition of the alkyl group from the Grignard derivatives and the methyl group from the trimethylaluminum occurs from opposite sides of the heterocycle, yielding the final primary amines with the same stereochemistry.
- Andrés, Celia,Nieto, Javier,Pedrosa, Rafael,Villama?án, Nieves
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p. 4130 - 4135
(2007/10/03)
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- SYNTHESIS OF THE RACEMIC FORM OF (Z)-1,17-DIAMINOOCTADEC-9-ENE, AN ALIPHATIC DIAMINE FROM COCCINELLIDAE. DETERMINATION OF THE ABSOLUTE CONFIGURATION OF THE (+)-NATURALLY-OCCURRING ANTIPODE
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The total synthesis of the title compound (1) has been achieved.Also reported is the use of lanthanide induced shifts in 1H NMR spectroscopy to assign the absolute configuration of the α-carbon atom in chiral primary α-methylalkylamines.Application of this empirical method to natural (+)-1 shows that it has the R-configuration at C-17.
- Braconnier, M.F.,Braekman, J.C.,Daloze, D.
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p. 605 - 614
(2007/10/02)
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