- Base-Catalyzed Hydrosilylation of Nitriles to Amines and Esters to Alcohols
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Base-catalyzed hydrosilylation of nitriles to amines and esters to silylated alcohols is reported. This protocol tolerates electron-rich and electron-neutral olefins and works in the presence of basic functional groups (e. g. tertiary amines) but fails for acidic substrates, such as phenols and NH anilines. This catalytic system does not tolerate carbonyl groups, such as aldehydes, ketones, esters and carbamides, which are reduced to corresponding alcohols and amines. With the exact amount of silane, esters can be selectively reduced in the presence of nitriles, but the selectivity drops for the pairs ester/carboxamide and carboxamide/nitrile. Through competition experiments, the following preference in functional group reactivity was determined: ester > carboxamide > nitrile.
- Clarke, Joshua A.,Nikonov, Georgii I.,van der Est, Art
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supporting information
p. 4434 - 4439
(2021/08/30)
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- Cobalt pincer complexes for catalytic reduction of nitriles to primary amines
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Various cobalt pincer type complexes 1-6 were applied for the catalytic hydrogenation of nitriles to amines. Among these, catalyst 4 is the most efficient, allowing the reduction of aromatic as well as aliphatic nitriles in moderate to excellent yields.
- Schneek?nig, Jacob,Tannert, Bianca,Hornke, Helen,Beller, Matthias,Junge, Kathrin
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p. 1779 - 1783
(2019/04/27)
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- Catalytic Staudinger Reduction at Room Temperature
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We report an efficient catalytic Staudinger reduction at room temperature that enables the preparation of a structurally diverse set of amines from azides in excellent yields. The reaction is based on the use of catalytic amounts of triphenylphosphine as a phosphine source and diphenyldisiloxane as a reducing agent. Our catalytic Staudinger reduction exhibits a high chemoselectivity, as exemplified by reduction of azides over other common functionalities, including nitriles, alkenes, alkynes, esters, and ketones.
- Lenstra, Danny C.,Wolf, Joris J.,Mecinovi?, Jasmin
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p. 6536 - 6545
(2019/05/24)
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- Hydrosilane Reduction of Nitriles to Primary Amines by Cobalt-Isocyanide Catalysts
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Reduction of nitriles to silylated primary amines was achieved by combination of 1,1,3,3-tetramethyldisiloxane (TMDS) as the hydrosilane and a catalytic amount of Co(OPIV)2 (PIV = COtBu) associated with isocyanide ligands. The resulting silylated amines were subjected to acid hydrolysis or treatment with acid chlorides to give the corresponding primary amines or imides in good yields. One-pot synthesis of primary amides to primary amines with hydrosilanes was also achieved by iron-cobalt dual catalyst systems.
- Sanagawa, Atsushi,Nagashima, Hideo
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supporting information
p. 287 - 291
(2019/01/10)
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- Sustainable organophosphorus-catalysed Staudinger reduction
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A highly efficient and sustainable catalytic Staudinger reduction for the conversion of organic azides to amines in excellent yields has been developed. The reaction displays excellent functional group tolerance to functionalities that are otherwise prone to reduction, such as sulfones, esters, amides, ketones, nitriles, alkenes, and benzyl ethers. The green nature of the reaction is exemplified by the use of PMHS, CPME, and a lack of column chromatography.
- Lenstra, Danny C.,Lenting, Peter E.,Mecinovi?, Jasmin
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p. 4418 - 4422
(2018/10/17)
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- Transfer hydrogenation of ketones, nitriles, and esters catalyzed by a half-sandwich complex of ruthenium
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Half-sandwich complexes [Cp(PiPr3)Ru(CH3CN)2]PF6 (1; Cp = cyclopentadienyl) and [Cp(phen)Ru(CH3CN)]PF6 (2; Cp = pentamethylcyclopentadienyl, phen = phenanthroline) catalyse the transfer hydrogenation of ketones to alcohols, aldimines to amines, and nitriles to imines under mild conditions. In the latter process, the imine products come from the coupling of the amines formed initially with acetone derived from the reducing solvent (isopropanol). Among functionally substituted nitriles, the aldo and keto groups are reduced concomitantly with the cyano group, whereas ester and amido groups are tolerated. Amides and alkyl esters are not reduced under these conditions even upon heating to 70°C. However, phenylbenzoates and trifluoroacetates are reduced to alcohols. Kinetic studies on the reduction of acetophenone in isopropanol established that the reaction is first order in both the substrate and the alcohol. Stoichiometric mechanistic studies showed the formation of a hydride species. A hydride mechanism was proposed to account for these observations.
- Lee, Sun-Hwa,Nikonov, Georgii I.
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p. 107 - 113
(2015/01/30)
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- Hydrogenation of esters to alcohols with a well-defined iron complex
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We present the first base-free Fe-catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer-sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments.
- Werkmeister, Svenja,Junge, Kathrin,Wendt, Bianca,Alberico, Elisabetta,Jiao, Haijun,Baumann, Wolfgang,Junge, Henrik,Gallou, Fabrice,Beller, Matthias
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supporting information
p. 8722 - 8726
(2014/08/18)
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- Positive cooperativity in the template-directed synthesis of monodisperse macromolecules
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Two series of oligorotaxanes R and R′ that contain -CH 2NH2+CH2- recognition sites in their dumbbell components have been synthesized employing template-directed protocols. [24]Crown-8 rings self-assemble by a c
- Belowich, Matthew E.,Valente, Cory,Smaldone, Ronald A.,Friedman, Douglas C.,Thiel, Johannes,Cronin, Leroy,Stoddart, J. Fraser
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experimental part
p. 5243 - 5261
(2012/05/20)
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- IMIDAZOLE CARBOXAMIDES
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The present invention provides certain imidazole carboxamide derivatives, pharmaceutical compositions thereof, methods of using the same and processes for preparing the same.
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Page/Page column 21
(2010/02/17)
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- Structure-activity relationship studies of 5-benzylaminoimidazo[1,2-c]pyrimidine-8-carboxamide derivatives as potent, highly selective ZAP-70 kinase inhibitors
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Zeta-associated protein, 70 kDa (ZAP-70), a spleen tyrosine kinase (Syk) family kinase, is normally expressed on T cells and natural killer cells and plays a crucial role in activation of the T cell immunoresponse. Thus, selective ZAP-70 inhibitors might
- Hirabayashi, Akihito,Mukaiyama, Harunobu,Kobayashi, Hiroaki,Shiohara, Hiroaki,Nakayama, Satoko,Ozawa, Motoyasu,Miyazawa, Keiji,Misawa, Keiko,Ohnota, Hideki,Isaji, Masayuki
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experimental part
p. 284 - 294
(2011/02/28)
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