598-56-1Relevant articles and documents
Deoxygenation of primary amides to amines with pinacolborane catalyzed by Ca[N(SiMe3)2]2(THF)2
Gong, Mingliang,Guo, Chenjun,Jiang, Linhong,Luo, Yunjie,Yu, Chong
supporting information, p. 1201 - 1206 (2021/05/29)
Deoxygenative reduction of amides is a challenging but favorable synthetic method of accessing amines. In the presence of a catalytic amount of Ca[N(SiMe3)2]2(THF)2, pinacolborane (HBpin) could efficiently reduce a broad scope of amides, primary amides in particular, into corresponding amines. Functional groups and heteroatoms showed good tolerance in this process of transformation, and a plausible reaction mechanism was proposed.
Lithium compound catalyzed deoxygenative hydroboration of primary, secondary and tertiary amides
Bisai, Milan Kumar,Gour, Kritika,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
supporting information, p. 2354 - 2358 (2021/03/03)
A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. This journal is
Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
supporting information, p. 13122 - 13135 (2021/08/31)
Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
supporting information, (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
Organic amine mediated cleavage of Caromatic-Cαbonds in lignin and its platform molecules
Cheng, Xiaomeng,Dong, Minghua,Han, Buxing,Liu, Huizhen,Liu, Shulin,Shen, Xiaojun,Wang, Zhenpeng,Xin, Yu,Yang, Junjuan
, p. 15110 - 15115 (2021/12/04)
The activation and cleavage of C-C bonds remains a critical scientific issue in many organic reactions and is an unmet challenge due to their intrinsic inertness and ubiquity. Meanwhile, it is crucial for the valorization of lignin into high-value chemicals. Here, we proposed a novel strategy to enhance the Caromatic-Cα bond cleavage by pre-functionalization with amine sources, in which an active amine intermediate is first formed through Markovnikov hydroamination to reduce the dissociation energy of the Caromatic-Cα bond which is then cleaved to form target chemicals. More importantly, this strategy provides a method to achieve the maximum utilization of the aromatic nucleus and side chains in lignin or its platform molecules. Phenols and N,N-dimethylethylamine compounds with high yields were produced from herbaceous lignin or the p-coumaric acid monomer in the presence of industrially available dimethylamine (DMA). This journal is
Bench-Stable Cobalt Pre-Catalysts for Mild Hydrosilative Reduction of Tertiary Amides to Amines and Beyond
Nurseiit, Alibek,Janabel, Jaysan,Gudun, Kristina A.,Kassymbek, Aishabibi,Segizbayev, Medet,Seilkhanov, Tulegen M.,Khalimon, Andrey Y.
, p. 790 - 798 (2019/01/09)
The readily synthesized and bench-stable cobalt dichloride complex (dpephos)CoCl2 is employed as a pre-catalyst for a diversity of silane additions to unsaturated organic molecules, including the normally challenging reduction of amides to amines. With regard to hydrosilative reduction of amides even more effective and activator free catalytic systems can be generated from the bench-stable, commercially available Co(acac)2 and Co(OAc)2 with dpephos and PPh3 ligands. These systems operate under mild conditions (100 °C), with many examples of room temperature transformations, presenting a first example of mild cobalt-catalyzed hydrosilylation of amides.
Hydrogenolysis of Amide Acetals and Iminium Esters
Kadyrov, Renat
, p. 170 - 172 (2017/12/26)
Amide acetals and iminium esters were hydrogenated into amines under very mild reaction conditions over common hydrogenation catalysts. This finding provides a new strategy for the selective reduction of amides. The synthetic utility of this approach was demonstrated by the selective reduction of amides bearing ester and nitrile groups.
Zinc hydridotriphenylborates supported by a neutral macrocyclic polyamine
Mukherjee, Debabrata,Wiegand, Ann-Kristin,Spaniol, Thomas P.,Okuda, Jun
supporting information, p. 6183 - 6186 (2017/07/11)
The zinc hydridotriphenylborates [(L)Zn(TMDS)][HBPh3] and [(L)ZnX][HBPh3] (L = Me4TACD, Me4[12]aneN4; TMDS = N(SiHMe2)2; X = Cl, Br, I) were synthesized by BPh3-mediated β-SiH abstraction and salt metathesis with KHBPh3, respectively. CO2 is rapidly inserted into the B-H bonds. [(L)Zn(TMDS)][HBPh3] catalyzes the hydroboration of polar substrates including CO2.
Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane
Mukherjee, Debabrata,Shirase, Satoru,Mashima, Kazushi,Okuda, Jun
supporting information, p. 13326 - 13329 (2016/10/30)
Triphenylborane (BPh3) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3may be mechanistically different from that catalyzed by the more electrophilic B(C6F5)3.
Reactivity of a Molecular Magnesium Hydride Featuring a Terminal Magnesium-Hydrogen Bond
Schnitzler, Silvia,Spaniol, Thomas P.,Okuda, Jun
, p. 12997 - 13006 (2016/12/26)
The reactivity of the molecular magnesium hydride [Mg(Me3TACD·AliBu3)H] (1) featuring a terminal magnesium-hydrogen bond and an NNNN-type macrocyclic ligand, Me3TACD ((Me3TACD)H = Me3[12]aneN4 = 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane), can be grouped into protonolysis, oxidation, hydrometalation, (insertion), and hydride abstraction. Protonolysis of 1 with weak Br?nsted acids HX such as terminal acetylenes, amines, silanols, and silanes gave the corresponding derivatives [Mg(Me3TACD·AliBu3)X] (X = C=CPh, 3; HN(3,5-Me2-C6H3), 4; OSiMe3, 5; OSiPh3, 6; Cl, 7; Br, 8). Single-crystal X-ray diffraction of anilide 4 showed a square-pyramidal coordination geometry for magnesium. No correlation with the pKa values of the acids was detected. Oxidation of 1 with elemental iodine gave the iodide [Mg(Me3TACD·AliBu3)I] (9), and oxidation with nitrous oxide afforded the μ-oxo-bridged compound [{Mg(Me3TACD·AliBu3)}2(μ-O)] (10) with a linear Mg-O-Mg core, as characterized by single-crystal X-ray diffraction. The Mg-H bond reacted with benzaldehyde, benzophenone, fluorenone, and CO2 under insertion but not with the olefins 1,1,2-triphenylethylene, tert-butylethylene, and cyclopentene. The unstable formate, prepared also by salt metathesis of iodide 9 with potassium formate, revealed ?°O,?°O′ coordination in the solid state. Hydride abstraction with triphenylborane gave the ion pair [Mg(Me3TACD·AliBu3)(thf)][HBPh3] (16), which catalyzed the hydroboration of polar substrates by pinacolborane.
