A Scrutiny on the Reductive Amination of Carbonyl Compounds Catalyzed by Homogeneous Rh(I) Diphosphane Complexes
摘要:
The reductive amination of a series of aldehydes with secondary amines and H-2 in the presence of a homogeneous Rh-diphosphane catalyst was studied in order to establish a general mechanism of this reaction and to identify conditions for the improvement of the amine/alcohol ratio in the product. Several possible intermediates as constituents of changing equilibria like half-aminals. N,O-acetals and aminals were observed in the reaction mixture by means of H-1 NMR spectroscopy. In individual trials, these compounds could be successfully hydrogenated under the conditions applied for reductive amination (50 bar H-2 pressure, MeOH). Some evidence is accumulated that half-aminals and N,O-acetals might be key intermediates of the reductive amination. Moreover, it was found that the formation of the undesired product alcohol is likely based on the reduction of the starting carbonyl compound. However, due to numerous equilibria consisting of several intermediates, general conclusions are hard to be drawn. Proof will be given that, in several cases, the efficiency of the reductive amination of aliphatic aldehydes can be significantly improved by prehydrogenation of the cationic [Rh(dppb)(COD)](+) complex.
Method for producing amines by homogeneously catalyzed reductive amination of carbonyl compounds
申请人:Riermeier Thomas
公开号:US06884887B1
公开(公告)日:2005-04-26
The invention relates to the preparation of chiral or achiral amines by reaction of aldehydes or ketones with ammonia or primary or secondary amines in the presence of hydrogen and in the presence of homogeneous metal catalysts under mild conditions. Metal catalysts which can be used are complexes of late transition metals with chiral or achiral phosphorus-containing ligands.
Highly efficient and eco-friendly synthesis of tertiary amines by reductive alkylation of aldehydes with secondary amines over a Pt nanowires catalyst
作者:Junjie Wu、Shuanglong Lu、Danhua Ge、Hongwei Gu
DOI:10.1039/c5ra12299f
日期:——
A highly efficient and environmentally friendly method for the synthesis of tertiary amines by direct interaction of aldehydes with secondary amines was reported over a Pt NWs catalyst under mild reaction conditions.
On the reductive amination of aldehydes and ketones catalyzed by homogeneous Rh(i) complexes
作者:Vitali I. Tararov、Renat Kadyrov、Armin Börner、Thomas H. Riermeier
DOI:10.1039/b005777k
日期:——
The homogeneously catalyzedreductiveamination of aldehydes and ketones under smooth conditions is reported, showing for the first time, that Rh(I) catalysts based on chelating diphosphines and diphosphinites can be advantageously employed for this reaction, even for the production of chiral amino acid derivatives.
Base-Catalyzed Anti-Markovnikov Hydroamination of Vinylarenes – Scope, Limitations and Computational Studies
作者:Patricia Horrillo-Martínez、Kai C. Hultzsch、Adrià Gil、Vicenç Branchadell
DOI:10.1002/ejoc.200700147
日期:2007.7
The hydroamination of vinylarenes with primary and secondary amines was studied with catalytic amounts as low as 2 mol-% of LiN(SiMe3)2/TMEDA. Reactions proceeded readily at 120 °C in the absence of solvent to give selective anti-Markovnikov addition. Slow addition was observed at 25 °C with either electron-deficient p-chlorostyrene or secondary cyclic amines such as pyrrolidine, piperidine, or morpholine
3-dimesitylimidazole-2-ylidenes the novel [RhCl(cod)(carbene)] complexes 1-5 have been synthesized, characterized, and tested in the hydroaminomethylation of aromatic olefins. The influence of different ligands and reaction parameters on the catalytic activity was investigated in detail applying 1,1-diphenylethylene and piperidine as a model system. The scope and limitations of the novel catalysts is shown in the