- Intramolecular Base Catalysis in N-Benzylideneaniline Transimination by (Dimethylamino)alkylamines in Methanol
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The internal tertiary amino group in 2-(dimethylamino)ethylamine and 3-(dimethylamino)propylamine catalyzes proton transfer between nitrogen atoms of the gem-diamines formed in the course of the title reaction.
- Toullec, Jean,Razafindralambo, Romuald
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- 2,4,5-Trisubstituted thiazole building blocks by a novel multi-component reaction
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A novel multi-component reaction (MCR) of oxo-components, primary amines, thiocarboxylic acids and 3-bromo-2-isocyanoacrylates yielding 2,4,5-trisubstituted thiazole building blocks is described.
- Umkehrer, Michael,Kolb, Jürgen,Burdack, Christoph,Hiller, Wolfgang
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- Manganese-Catalyzed Selective Hydrogenative Cross-Coupling of Nitriles and Amines to Form Secondary Imines
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Manganese complexes with tridentate PNN ligands have been synthesized as catalysts for hydrogenative cross-coupling reaction of nitriles and amines to form secondary imines. This reaction afforded a variety of unsymmetrical secondary imines in good yields with excellent selectivity. Investigation of catalyst intermediates indicated that an amido manganese complex may be the active catalyst species for this reaction. (Figure presented.).
- Li, Xiao-Gen,Zhou, Qi-Lin
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supporting information
p. 3471 - 3475
(2021/04/29)
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- Magnesium catalysis of imine hydroboration
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The β-diketiminato magnesium alkyl complex [LMgnBu] (L=CH{CMe(NDipp)}2, Dipp=diisopropylphenyl) is shown to be a highly effective precatalyst for the hydroboration of alkyl and aryl substituted aldimines and ketimines with pinacol borane (HBpin). Catalysis is proposed to occur through a sequence of Mg-N/B-H metathesis and rate-determining Mg-H/N=C insertion steps, a proposal strongly supported by stoichiometric studies and kinetic analysis. The reactions are observed to proceed through the intermediacy of well-defined magnesium amides, two examples of which have been isolated and structurally characterized. Mechanistic investigations suggest that the catalytic rate-determining process occurs at an isolated magnesium center and requires the presence of two molecules of the imine substrate for effective turnover. This latter observation is rationalized as a requirement for the secondary substrate molecule to displace HBpin from the coordination sphere of the catalytic magnesium center.
- Arrowsmith, Merle,Hill, Michael S.,Kociok-Koehn, Gabriele
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supporting information
p. 2776 - 2783
(2013/03/14)
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- Nitrous oxide as a primary product in base-mediated β-elimination reactions of diazeniumdiolated benzylamine derivatives
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We report an unexpected β-elimination pathway by which diazeniumdiolated benzylamines of structure Bn-N(R)-N(O)N-OR′ undergo base-mediated fragmentation to generate N2O as the only gaseous product. The reaction is especially rapid for R = 2-hydroxyethyl, in which the hydroxyl group anchimerically assists benzylic proton removal with concomitant expulsion of PhCHNR and R′OH.
- Biswas, Debanjan,Cao, Zhao,Keefer, Larry K.,Saavedra, Joseph E.
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supporting information; experimental part
p. 5931 - 5933
(2012/08/14)
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- Iridium-catalyzed reduction of secondary amides to secondary amines and imines by diethylsilane
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Catalytic reduction of secondary amides to imines and secondary amines has been achieved using readily available iridium catalysts such as [Ir(COE) 2Cl]2 with diethylsilane as reductant. The stepwise reduction to secondary amine proceeds through an imine intermediate that can be isolated when only 2 equiv of silane is used. This system requires low catalyst loading and shows high efficiency (up to 1000 turnovers at room temperature with 99% conversion have been attained) and an appreciable level of functional group tolerance.
- Cheng, Chen,Brookhart, Maurice
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supporting information; experimental part
p. 11304 - 11307
(2012/09/05)
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- Controlled and chemoselective reduction of secondary amides
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This communication describes a metal-free methodology involving an efficient and controlled reduction of secondary amides to imines, aldehydes, and amines in good to excellent yields under ambient pressure and temperature. The process includes a chemoselective activation of a secondary amide with triflic anhydride in the presence of 2-fluoropyridine. The electrophilic activated amide can then be reduced to the corresponding iminium using triethylsilane, a cheap, rather inert, and commercially available reagent. Imines can be isolated after a basic workup or readily transformed to the aldehydes following an acidic workup. The amine moiety can be accessed via a sequential reductive amination by the addition of silane and Hantzsch ester hydride in a one-pot reaction. Moreover, this reduction tolerates various functional groups that are usually reactive under reductive conditions and is very selective to secondary amides.
- Pelletier, Guillaume,Bechara, William S.,Charette, Andre B.
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supporting information; experimental part
p. 12817 - 12819
(2010/11/05)
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- Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives
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A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2- dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4- dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.
- Vydzhak,Panchishin, S. Ya.
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experimental part
p. 2391 - 2397
(2009/05/30)
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- Titanium Induced Coupling of Imines to Symmetrical Vicinal (R*,R*)-Diamines
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Symmetrical vicinal (R*,R*) -d,l-diamines were prepared from the corresponding imines and low valent titanium species generated by the action of titanium tetrachloride on amalgamated magnesium.
- Mangeney, P.,Tejero, T.,Alexakis, A.,Grosjean, F.,Normant, J.
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p. 255 - 257
(2007/10/02)
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