31776-80-4Relevant academic research and scientific papers
Modular Photocatalytic Synthesis of α-Trialkyl-α-Tertiary Amines
Gaunt, Matthew J.,Harris, Georgia R.,Henry Blackwell, J.,Smith, Milo A.
, p. 15946 - 15959 (2021/10/12)
Molecules displaying an α-trialkyl-α-tertiary amine motif provide access to an important and versatile area of biologically relevant chemical space but are challenging to access through existing synthetic methods. Here, we report an operationally straightforward, multicomponent protocol for the synthesis of a range of functionally and structurally diverse α-trialkyl-α-tertiary amines, which makes use of three readily available components: dialkyl ketones, benzylamines, and alkenes. The strategy relies on the of use visible-light-mediated photocatalysis with readily available Ir(III) complexes to bring about single-electron reduction of an all-alkyl ketimine species to an α-amino radical intermediate; the α-amino radical undergoes Giese-type addition with a variety of alkenes to forge the α-trialkyl-α-tertiary amine center. The mechanism of this process is believed to proceed through an overall redox neutral pathway that involves photocatalytic redox-relay of the imine, generated from the starting amine-ketone condensation, through to an imine-derived product. This is possible because the presence of a benzylic amine component in the intermediate scaffold drives a 1,5-hydrogen atom transfer step after the Giese addition to form a stable benzylic α-amino radical, which is able to close the photocatalytic cycle. These studies detail the evolution of the reaction platform, an extensive investigation of the substrate scope, and preliminary investigation of some of the mechanistic features of this distinct photocatalytic process. We believe this transformation will provide convenient access to previously unexplored α-trialkyl-α-tertiary amine scaffolds that should be of considerable interest to practitioners of synthetic and medicinal chemistry in academic and industrial institutions.
Base-Free Oxidative Coupling of Amines and Aliphatic Alcohols to Imines over Au–Pd/ZrO2 Catalyst under Mild Conditions
Cui, Wenjing,Jia, Meilin,Sagala,Wang, Jiang
, p. 958 - 967 (2021/06/06)
Abstract: The base-free synthesis of imines from amines and aliphatic alcohols over Au–Pd alloy catalysts under ambient conditions was developed. A series of Au–Pd/ZrO2 bimetallic catalysts with varying metal loadings and Au?:?Pd molar ratios were prepared and their catalytic performance was investigated. The 3.0?wt?% Au–Pd/ZrO2 alloy catalyst with Au?:?Pd molar ratio of 1?:?1 showed the best catalytic performance. Under air atmosphere, various imines were obtained from coupling of amines and aliphatic alcohols without any additives or promoters. The performance of alloy NPs was superior to that of monometallic catalysts due to the synergistic effect which was demonstrated by TEM, XPS, and UV–Vis characterization. Our work suggested this transformation differed slightly from those reactions between amine and benzyl alcohol and a possible mechanism was proposed. Moreover, the Au–Pd/ZrO2 catalyst could be easily separated and reused for at least five successive runs with high catalytic activity.
Manganese-Catalyzed Transfer Hydrogenation of Nitriles with 2-Butanol as the Hydrogen Source
Gardu?o, Jorge A.,Flores-Alamo, Marcos,García, Juventino J.
, p. 5330 - 5338 (2019/11/03)
We report herein the first example of a homogeneous manganese catalyzed transfer hydrogenation of nitriles using 2-BuOH as the hydrogen source. Compound fac-[(CO)3Mn{iPr2P(CH2)2PiPr2}Br] (Mn-1, 3 mol %) exhibited catalytic activity in the presence of KOtBu (10 mol %) for the transfer hydrogenation of benzonitrile to yield a mixture of benzylamine (BA) and N-sec-butylidenebenzylamine (SBA). Subsequent acidic hydrolysis yielded isolated benzylamine hydrochloride in 96 %. The title system featured reversible formation of N-benzylidenebenzylamine (BBA) prior to formation of SBA. A series of amine hydrochlorides was prepared following this methodology (39–92 % isolated yields, 4 examples). Best substrates for this transformation are electron-rich aromatic nitriles, nonetheless electron-deficient aromatic as well as aliphatic nitriles were also hydrogenated. Mechanistic studies suggested coordinatively unsaturated Mn-hydride species performing catalytic turnover.
Application of tris(trimethylsilyl) phosphite as a convenient phosphorus nucleophile in the direct synthesis of tetrasubstituted α-aminophosphonic acids from ketimines
Boduszek, Bogdan,Olszewski, Tomasz K.
, p. 173 - 179 (2017/03/06)
The condensation of tris(trimethylsilyl) phosphite with various ketimines leads directly to tetrasubstituted a-aminophosphonic acids. The presented reaction proceeds readily at room temperature and provides labile silylated esters of tetrasubstituted a-aminophosphonic acids, as non-isolable reaction intermediates. Subsequent methanolysis of the latter provides the desired á-aminophosphonic acids bearing an fully substituted á-carbon in good overall yields as crystalline non-hygroscopic solids after simple recrystallization from a methanol-acetone mixture.nordstom.
Synthesis of imines from amines in aliphatic alcohols on Pd/ZrO2 catalyst under ambient conditions
Cui, Wenjing,Zhaorigetu, Bao,Jia, Meilin,Ao, Wulan,Zhu, Huaiyong
, p. 2601 - 2604 (2014/01/06)
Synthesis of imines from amines and aliphatic alcohols (C 1-C6) in the presence of base on supported palladium nanoparticles has been achieved for the first time. The catalytic system shows high activity and selectivity in open air at room temperature.
An easy synthesis of α-trifluoromethyl-amines from aldehydes or ketones using the Ruppert-Prakash reagent
Radchenko, Dmytro S.,Michurin, Oleg M.,Chernykh, Anton V.,Lukin, Oleg,Mykhailiuk, Pavel K.
supporting information, p. 1897 - 1898 (2013/04/24)
A small library of structurally diverse primary amines bearing a geminal CF3 group was synthesized on a preparative scale. The synthesis starts with an aldehyde or ketone that reacts with benzylamine yielding the corresponding imine. The latter is then trifluoromethylated with Me 3SiCF3 under acidic conditions to give a benzylalkylamine. In the last step the Pd-mediated hydrogenation of the benzylalkylamines furnishes the title compounds. All synthetic steps are high-yielding; neither the isolation of the intermediates nor the chromatographic purification of the products is necessary.
α-Benzylation of Ketones by Reaction with Benzylamine. Regioselective Reduction of C-C Double Bonds in Cohjugated Enones
Armesto, Diego,Esteban, Soledad,Horspool, William M.,Martin, Juan-Antonio F.,Martinez-Alcazar, Paz,Perez-Ossorio, Rafael
, p. 751 - 755 (2007/10/02)
Prolonged reaction of some ketones with benzylamine at reflux converts them into α-benzyl derivatives by a route involving Aldol condensation of the related ketimine with benzaldimine followed by exclusive reduction of the resultant C-C double bond.Reduction does not occur when pure benzylamine is used under oxygen-free nitrogen, however the inclusion of a trace of benzaldehyde restores the efficiency of the reaction.Treatment of several ketones in this manner established the scope of the process.When the reaction was extended to the reduction of α,β-unsaturated enones again using benzylamine, reaction times were shorter and the product yield greater.The possibility that the reductive step was an intramolecular 1,5-hydrogen transfer was studied.
