4128-67-0Relevant academic research and scientific papers
Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines
Esteruelas, Miguel A.,Lezáun, Virginia,Martínez, Antonio,Oliván, Montserrat,Onate, Enrique
, p. 2996 - 3004 (2017)
The preparation of new osmium hydride complexes, starting from OsH6(PiPr3)2 (1) and OsH2Cl2(PiPr3)2 (2), and their catalytic activity in acceptorless dehydrogenative coupling of alcohols and amines and in dehydrogenation of cyclic amines are reported. Complex 1 reacts with acetylacetone (Hacac) to give the classical trihydride OsH3(acac)(PiPr3)2 (3). The protonation of 3 with triflic acid (HOTf) produces the release of H2 and the formation of the unsaturated osmium(IV) dihydride [OsH2(acac)(PiPr3)2]OTf (4), which is also prepared by starting from 2 via the intermediate OsH2Cl(acac)(PiPr3)2 (5). Treatment of an acetylacetone solution of 5 with KOH affords Os(acac)2(PiPr3)2 (6). In the presence of 5 mol % of KOH, complexes 3-6 promote the coupling of benzyl alcohol and aniline to give N-benzylideneaniline and H2. Under the same conditions, complex 3 catalyzes a wide range of analogous couplings to afford a variety of imines, including aliphatic imines, with yields between 90 and 40% after 1-48 h. Complex 3 also catalyzes the dehydrogenation of cyclic amines. According to the amount of H2 released by each 1 g of employed substrate, the amines have been classified into three classes: poor (1,2,3,4-tetrahydroquinaldine, 2-methylindoline, and 2,6-dimethylpiperidine), moderate (1,2,3,4-tetrahydroquinoline and 6-methyl-1,2,3,4-tetrahydroquinoline), and good hydrogen donors (1,2,3,4-tetrahydroisoquinoline).
Divergent Coupling of Alcohols and Amines Catalyzed by Isoelectronic Hydride MnIand FeIIPNP Pincer Complexes
Mastalir, Matthias,Glatz, Mathias,Gorgas, Nikolaus,St?ger, Berthold,Pittenauer, Ernst,Allmaier, Günter,Veiros, Luis F.,Kirchner, Karl
supporting information, p. 12316 - 12320 (2016/08/24)
Herein, we describe an efficient coupling of alcohols and amines catalyzed by well-defined isoelectronic hydride MnIand FeIIcomplexes, which are stabilized by a PNP ligand based on the 2,6-diaminopyridine scaffold. This reaction is an environmentally benign process implementing inexpensive, earth-abundant non-precious metal catalysts, and is based on the acceptorless alcohol dehydrogenation concept. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted in good to excellent isolated yields. Although in the case of Mn selectively imines were obtained, with Fe—exclusively monoalkylated amines were formed. These reactions proceed under base-free conditions and required the addition of molecular sieves.
1-Butyl-1-methylpyrrolidinium hydrogen sulfate-promoted preparation of 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-one derivatives
Ghashang, Majid
, p. 2187 - 2195 (2013/06/26)
A convenient preparative approach for synthesis of various 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones promoted by 1-butyl-1- methylpyrrolidinium hydrogen sulfate is developed which involves cyclocondensation of aldehydes with amines and ethyl pyruvate under ambient conditions. Graphical abstract: A convenient preparative approach for synthesis of various 1,5-diaryl-3-(arylamino)-1H-pyrrol-2(5H)-ones promoted by 1-butyl-1-methylpyrrolidinium hydrogen sulfate is developed which involves cyclocondensation of aldehydes with amines and ethyl pyruvate under ambient conditions.[Figure not available: see fulltext.]
