- Iron-catalysed 1,2-aryl migration of tertiary azides
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1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
- Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
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p. 11685 - 11688
(2020/10/19)
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- Lithium–Bromide Exchange versus Nucleophilic Addition of Schiff's base: Unprecedented Tandem Cyclisation Pathways
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By exploring lithium–bromide exchange reactivity of aromatic Schiff's bases with tert-butyllithium (tBuLi), we have revealed unprecedented competitive intermolecular and intramolecular cascade annulation pathways, leading to valuable compounds, such as iso-indolinones and N-substituted anthracene derivatives. A series of reaction parameters were probed, including solvent, stoichiometry, sterics and organolithium reagent choice, in order to understand the influences that limit such ring-closing pathways. With two viable reactivity options for the organolithium on the imine; namely, nucleophilic addition or lithium–bromide exchange, a surprising competitive nature was observed, where nucleophilic addition dominated, even under cryogenic conditions. Considering the most commonly used solvents for lithium–bromide exchange, tetrahydrofuran (THF) and diethyl ether (Et2O), contrasting reactivity outcomes were revealed with nucleophilic addition promoted in THF, while Et2O yielded almost double the conversion of cyclic products than in THF.
- Orr, Samantha A.,Border, Emily C.,Andrews, Philip C.,Blair, Victoria L.
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supporting information
(2019/08/16)
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- Unprecedented Nucleophilic Additions of Highly Polar Organometallic Compounds to Imines and Nitriles Using Water as a Non-Innocent Reaction Medium
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In contrast to classic methods carried out under inert atmospheres with dry volatile organic solvents and often low temperatures, the addition of highly polar organometallic compounds to non-activated imines and nitriles proceeds quickly, efficiently, and chemoselectively with a broad range of substrates at room temperature and under air with water as the only reaction medium. Secondary amines and tertiary carbinamines are furnished in yields of up to and over 99 %. The significant solvent D/H isotope effect observed for the on-water nucleophilic additions of organolithium compounds to imines suggests that the on-water catalysis arises from proton transfer across the organic–water interface. The strong intermolecular hydrogen bonds between water molecules may play a key role in disfavoring protonolysis, which occurs extensively in other protic media such as methanol. This work lays the foundation for reshaping many fundamental s-block metal-mediated organic transformations in water.
- Dilauro, Giuseppe,Dell'Aera, Marzia,Vitale, Paola,Capriati, Vito,Perna, Filippo Maria
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supporting information
p. 10200 - 10203
(2017/08/14)
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- Exploiting Deep Eutectic Solvents and Organolithium Reagent Partnerships: Chemoselective Ultrafast Addition to Imines and Quinolines Under Aerobic Ambient Temperature Conditions
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Shattering the long-held dogma that organolithium chemistry needs to be performed under inert atmospheres in toxic organic solvents, chemoselective addition of organolithium reagents to non-activated imines and quinolines has been accomplished in green, b
- Vidal, Cristian,García-álvarez, Joaquín,Hernán-Gómez, Alberto,Kennedy, Alan R.,Hevia, Eva
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supporting information
p. 16145 - 16148
(2016/12/26)
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- Development of highly enantioselective new Lewis basic N-formamide organocatalysts for hydrosilylation of imines with an unprecedented substrate profile
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l-Pipecolinic acid derived N-formamides have been developed as new Lewis basic organocatalysts that promote the asymmetric reduction of N-aryl ketimines using trichlorosilane as the reducing agent. The substituent on N4 of the piperazinyl backbone and the
- Wu, Pengcheng,Wang, Zhouyu,Cheng, Mounuo,Zhou, Li,Sun, Jian
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experimental part
p. 11304 - 11312
(2009/04/06)
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- Novel one-pot synthesis of N-alkyl arylamines from oxime ethers using organometallic reagents
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A novel one-pot synthesis of α,α-disubstituted secondary arylamines from oxime ethers has been developed by two separate additions of organometallic reagents. As a related arylamine construction, very efficient synthesis of N-(diallyl)methyl arylamines is
- Mukhopadhyay, Partha P.,Miyata, Okiko,Naito, Takeaki
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p. 1403 - 1406
(2008/02/13)
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- L-piperazine-2-carboxylic acid derived N-formamide as a highly enantioselective Lewis basic catalyst for hydrosilylation of N-aryl imines with an unprecedented substrate profile
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L-Piperazine-2-carboxylic acid derived N-formamides have been developed as highly enantioselective Lewis basic catalysts for the hydrosilylation of N-aryl imines with trichlorosilane. The arene sulfonyl group on N4 was found to be critical for the high en
- Wang, Zhouyu,Cheng, Mounuo,Wu, Pengcheng,Wei, Siyu,Sun, Jian
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p. 3045 - 3048
(2007/10/03)
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- Highly efficient alkylation to ketones and aldimines with Grignard reagents catalyzed by zinc(II) chloride
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A highly efficient alkylation to ketones and aldimines with Grignard reagents in the presence of catalytic trialkylzinc(II) ate complexes derived from ZnCl2 (10 mol %) in situ was developed. This simple Zn(II)-catalyzed alkylation could minimize the well-known but serious problems with the use of only Grignard reagents, which leads to reduction and aldol side products, and the yield of desired alkylation products could be improved. Copyright
- Hatano, Manabu,Suzuki, Shinji,Ishihara, Kazuaki
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p. 9998 - 9999
(2007/10/03)
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- Regio- and stereoselective double alkylation of β-enamino esters with organolithium reagents followed by one-pot reduction: convenient method for the synthesis of tertiary γ-amino alcohols
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An easy, high yielding and stereoselective procedure for the preparation of tertiary γ-amino alcohols starting from β-enamino esters is presented. In this procedure, the double alkylation of β-enamino esters with organolithium reagents is followed by one-
- Cimarelli, Cristina,Palmieri, Gianni,Volpini, Emanuela
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p. 9423 - 9432
(2007/10/03)
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- Novel domino elimination-rearrangement-addition reaction of N-alkoxy(arylmethyl)amines to N-alkyl arylamines
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A new domino reaction of N-alkoxy(arylmethyl)amines to N-alkyl arylamines, consisting of three types of reactions: elimination of alcohol, rearrangement of the aryl group, and addition of an organolithium or a magnesium reagent, has been developed for the first time. Georg Thieme Verlag Stuttgart.
- Miyata, Okiko,Ishikawa, Tatsuya,Ueda, Masafumi,Naito, Takeaki
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p. 2219 - 2222
(2007/10/03)
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- Addition of trialkylalanes to imines under zirconium catalysis
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Trialkylalanes, which are inert toward imines, undergo addition to them in the presence of a catalytic amount of dichlorodicyclopentadienylzirconium(IV) (Cp2ZrCl2). The reaction tolerates the presence of several functional groups in the starting imine such as halo, amide, nitrile, and hydroxy groups. A possible reaction pathway is proposed involving metallacyclic intermediates. Georg Thieme Verlag Stuttgart.
- Denhez, Clement,Vasse, Jean-Luc,Szymoniak, Jan
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p. 2075 - 2079
(2007/10/03)
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- A one-pot aza-Wittig based solution and polymer supported route to amines
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This paper presents a high yielding one-pot solution phase and polymer supported synthesis of a range of primary and secondary amines starting from azides and aldehydes. The synthesis utilises a tandem process which begins with an aza-Wittig reaction between the aldehyde and an iminophosphorane, followed by reduction, or organometallic 1,2-addition reaction, of the resultant imine. The requisite iminophosphoranes were accessed using the highly efficient Staudinger reaction between the azide starting material and a phosphine. The process was applicable to the solid phase by the use of polymer supported iminophosphoranes and polymer supported cyanoborohydride.
- Hemming,Bevan,Loukou,Patel,Renaudeau
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p. 1565 - 1568
(2007/10/03)
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- Synthesis and application of ligands for the asymmetric addition of organolithium reagents to imines
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Amino acid derived ligands 4d,e are prepared from (S)-valine and (S)-proline respectively, and can be used as chiral ligands during the asymmetric addition of organolithium reagents to N-arylimines. Ligand 4e, which is prepared by two independent routes, is found to induce addition of organolithium reagents to the si-face of the imines, whilst ligand 4d in common with the previously reported catalysts 4a-c induces addition to the re-face of the imines.
- Jones, Catrin A.,Jones, Iwan G.,Mulla, Mushtaq,North, Michael,Sartori, Lucia
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p. 2891 - 2896
(2007/10/03)
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- Asymmetric reductions of imines and ketones by chiral oxaborolidines
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Asymmetric reduction of imines were studied using dialkoxyborane 1. Dihydro-β-carboline 5a showed moderate (42% ee) and N-phenylketimine 10 higher enantioselectivity (73% ee). Asymmetric reduction of ketones with oxazaborolidine 33 showed high enantioselectivities.
- Nakagawa,Kawate,Kakikawa,Yamada,Matsui,Hino
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p. 1739 - 1748
(2007/10/02)
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- Asymmetric reduction of imines with chiral dialkoxyboranes
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The asymmetric reduction of imines with chiral dialkoxyboranes was investigated and gave an optically active amine up to 73%ee in the presence of MgBr2·OEt2.
- Kawate,Nakagawa,Kakikawa,Hino
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p. 227 - 230
(2007/10/02)
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- ANION RADICAL-INDUCED DESILYLATION OF ORGANOSILANE. REACTIONS OF BENZYLSILANES WITH ALDEHYDES AND RELATED COMPOUNDS IN THE PRESENCE OF BUTYLLITHIUM OR LITHIUM METAL
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By the action of butyllithium or lithium metal in such polar aprotic solvent as DMF or HMPA in the presence of aldehydes or related compounds, some benzylsilanes suffer from anion radicalinduced desilylation forming benzyl carbanions which add to the aldehydes and related compounds.
- Kanemasa, Shuji,Tanaka, Junji,Nagahama, Hideki,Tsuge, Otohiko
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p. 1223 - 1226
(2007/10/02)
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