Catalysis Research Laboratory (CaRLa) , Im Neuenheimer Feld 584, 69120 Heidelberg, Germany.
BASF SE , Quantum Chemistry and Molecular Simulation, Carl-Bosch-Strasse 38, 67056 Ludwigshafen, Germany.
J Am Chem Soc. 2018 Jan 10;140(1):355-361. doi: 10.1021/jacs.7b10496. Epub 2017 Dec 26.
The asymmetric ruthenium-catalyzed reductive amination employing ammonia and hydrogen to primary amines is described. Here we demonstrate the capability of our catalyst to perform a chemo- and enantioselective process while using simple ammonia gas as a reagent, one of the most attractive and industrially relevant nitrogen sources. The presence of a catalytic amount of ammonium iodide was essential for obtaining good yields and enantioselectivities. The mechanism of this reaction was investigated by DFT and we found a viable pathway that also explains the trend and magnitude of enantioselectivity through the halide series in good agreement with the experimental data. The in-depth investigation of substrate conformers during the reaction turned out to be crucial in obtaining an accurate prediction of the enantioselectivity. Furthermore, we report the crystallographic data of the chiral [Ru(I)H(CO)((S,S)-f-binaphane)(PPh)] complex, which we identified as the most efficient catalyst in our investigation.
本文描述了不对称钌催化的还原胺化反应，该反应采用氨和氢气作为还原剂来合成伯胺。在这里，我们展示了我们的催化剂的能力，即在使用简单的氨气作为试剂时，能够进行化学选择性和对映选择性的过程，而氨气是最具吸引力和工业相关的氮源之一。催化量的碘化铵的存在对于获得良好的产率和对映选择性是至关重要的。通过 DFT 研究了该反应的机理，我们发现了一条可行的途径，该途径也通过卤化物系列很好地解释了对映选择性的趋势和幅度，与实验数据非常吻合。在反应过程中深入研究底物构象对于获得准确的对映选择性预测至关重要。此外，我们还报道了手性[Ru(I)H(CO)((S,S)-f-binaphane)(PPh)]配合物的晶体学数据，我们将其鉴定为我们研究中最有效的催化剂。
