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- ItemEfficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese-PNN pincer complex(Cambridge : RSC, 2017) Papa, Veronica; Cabrero-Antonino, Jose R.; Alberico, Elisabetta; Spanneberg, Anke; Junge, Kathrin; Junge, Henrik; Beller, MatthiasNovel well-defined NNP and PNP manganese pincer complexes have been synthetized and fully characterized. The catalyst Mn-2 containing an imidazolyaminolphosphino ligand shows high activity and selectivity in the hydrogenation of a wide range of secondary and tertiary amides to the corresponding alcohols and amines, under relatively mild conditions. For the first time, more challenging substrates like primary aromatic amides including an actual herbicide can also be hydrogenated using this earth-abundant metal-based pincer catalyst.
- ItemTowards a general ruthenium-catalyzed hydrogenation of secondary and tertiary amides to amines(Cambridge : RSC, 2016) Cabrero-Antonino, Jose R.; Alberico, Elisabetta; Junge, Kathrin; Junge, Henrik; Beller, MatthiasA broad range of secondary and tertiary amides has been hydrogenated to the corresponding amines under mild conditions using an in situ catalyst generated by combining [Ru(acac)3], 1,1,1-tris(diphenylphosphinomethyl)ethane (Triphos) and Yb(OTf)3. The presence of the metal triflate allows to mitigate reaction conditions compared to previous reports thus improving yields and selectivities in the desired amines. The excellent isolated yields of two scale-up experiments corroborate the feasibility of the reaction protocol. Control experiments indicate that, after the initial reduction of the amide carbonyl group, the reaction proceeds through the reductive amination of the alcohol with the amine arising from collapse of the intermediate hemiaminal.
- ItemA general strategy for the synthesis of α-trifluoromethyl- and α-perfluoroalkyl-β-lactams via palladium-catalyzed carbonylation(Cambridge : RSC, 2021) Li, Yang; Zhang, Cai-Lin; Huang, Wei-Heng; Sun, Ning; Hao, Meng; Neumann, Helfried; Beller, Matthiasβ-Lactam compounds play a key role in medicinal chemistry, specifically as the most important class of antibiotics. Here, we report a novel one-step approach for the synthesis of α-(trifluoromethyl)-β-lactams and related products from fluorinated olefins, anilines and CO. Utilization of an advanced palladium catalyst system with the Ruphos ligand allows for selective cycloaminocarbonylations to give diverse fluorinated β-lactams in high yields. © The Royal Society of Chemistry 2021.
- ItemA robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones(Cambridge : RSC, 2018) Sahoo, Basudev; Kreyenschulte, Carsten; Agostini, Giovanni; Lund, Henrik; Bachmann, Stephan; Scalone, Michelangelo; Junge, Kathrin; Beller, MatthiasBy applying N-doped carbon modified iron-based catalysts, the controlled hydrogenation of N-heteroarenes, especially (iso)quinolones, is achieved. Crucial for activity is the catalyst preparation by pyrolysis of a carbon-impregnated composite, obtained from iron(ii) acetate and N-aryliminopyridines. As demonstrated by TEM, XRD, XPS and Raman spectroscopy, the synthesized material is composed of Fe(0), Fe3C and FeNx in a N-doped carbon matrix. The decent catalytic activity of this robust and easily recyclable Fe-material allowed for the selective hydrogenation of various (iso)quinoline derivatives, even in the presence of reducible functional groups, such as nitriles, halogens, esters and amides. For a proof-of-concept, this nanostructured catalyst was implemented in the multistep synthesis of natural products and pharmaceutical lead compounds as well as modification of photoluminescent materials. As such this methodology constitutes the first heterogeneous iron-catalyzed hydrogenation of substituted (iso)quinolones with synthetic importance.