1613-98-5Relevant academic research and scientific papers
Surface immobilized azomethine for multiple component exchange
Lerond, Michael,Bélanger, Daniel,Skene
, p. 6639 - 6646 (2017)
Diazonium chemistry concomitant with in situ electrochemical reduction was used to graft an aryl aldehyde to indium-tin oxide (ITO) coated glass substrates. This served as an anchor for preparing electroactive azomethines that were covalently bonded to th
Inverse Hydroboration of Imines with NHC-Boranes Is Promoted by Diphenyl Disulfide and Visible Light
Kawamoto, Takuji,Morioka, Tsubasa,Noguchi, Kohki,Curran, Dennis P.,Kamimura, Akio
supporting information, p. 1825 - 1828 (2021/03/08)
We describe a simple and efficient procedure for nucleophilic borylation of imines in the absence of a photoredox catalyst. Visible light irradiation of an acetonitrile solution of an imine, an NHC-borane, and diphenyl disulfide (10 mol %) provides various stable α-amino NHC-boranes in good yields. The reaction proceeds via addition of a nucleophilic boryl radical to an imine, followed by hydrogen abstraction from thiophenol, which is generated from NHC-borane and diphenyl disulfide.
Insight into the Modes of Activation of Pyridinium and Bipyridinium Salts in Non-Covalent Organocatalysis
Weiss, Robin,Golisano, Tamara,Pale, Patrick,Mamane, Victor
supporting information, p. 4779 - 4788 (2021/09/06)
A series of pyridinium and bipyridinium salts were prepared and their catalytic properties were evaluated in the aza-Diels-Alder reaction between imines and Danishefsky diene. Depending on the substituents of the pyridinium/bipyridinium rings and on the nature of the counterion, two mechanisms of activation were demonstrated. In case of non-substituted rings, the substrate is activated through charge transfer involving the aryl ring on the C-side of the imine. When halogen atoms were introduced on the catalysts, the activation mode switched to halogen bond involving the imine nitrogen lone pair. Moreover, alternative activation modes based on hydrogen bonding and radical cation were ruled out. This work allowed us to develop two families of catalysts whose potential was demonstrated in the cycloaddition of various imines with Danishefsky diene. The first family is composed of the simple methyl pyridinium triflate and dioctyl bipyridinium triflate. The former is active only with imines bearing a p-methoxyphenyl group on the C-side and the latter was found to be efficient with imines bearing different substituents on both the N- and C-sides of the imines. The second family is based on halogenated pyridinium salts which proved active with almost all considered imines. (Figure presented.).
Nickel Complexes Bearing N,N,O-Tridentate Salicylaldiminato Ligand: Efficient Catalysts for Imines Formation via Dehydrogenative Coupling of Primary Alcohols with Amines
Han, Zhangang,Hao, Zhiqiang,Lin, Jin,Lu, Guo-Liang,Zhang, Junhua,Zhang, Xiaoying
, p. 3843 - 3853 (2021/11/18)
Treatment of salicylaldiminato ligand L1H-L2H (L1H = 2,4-di-tert-butyl-6-((quinolin-8-ylimino)methyl)phenol; L2H = 2,4-di-tert-butyl-6-(((2-(diethylamino)ethyl)imino)methyl)phenol) with Ni(OAc)2·4H2O in refluxing ethanol afforded nickel complexes [(L1)Ni(OAc)] (1) and [(L2)Ni(OAc)] (2), respectively. Reaction of L3H (L3H = (2,4-di-tert-butyl-6-(((2-(pyridin-2-yl)ethyl)imino)methyl)phenol)) with Ni(OAc)2·4H2O in the presence of excess triethylanmine gave the dual ligands coordinated nickel complex [(L2)2Ni] (3). Complexes 1-3 were well characterized by high-resolution mass spectrometry, infrared spectroscopy, elemental analysis, and X-ray diffraction analysis. All the three Ni(II) complexes exhibited efficient activity and good selectivity in the acceptorless dehydrogenative coupling of alcohols and amines to produce imines and diimines. The present protocol provides an atom-economical and sustainable route for the synthesis of various imine derivatives by employing an earth-abundant nickel salt and easily prepared salicylaldiminato ligands.
A Highly Selective Manganese-Catalyzed Synthesis of Imines under Phosphine-Free Conditions
Chai, Huining,Yu, Kun,Liu, Bo,Tan, Weiqiang,Zhang, Guangyao
, p. 217 - 226 (2020/01/31)
An efficient and highly selective phosphine-free NN-manganese(I) complex catalyst system was developed for the acceptorless dehydrogenative coupling of alcohols with amines to form imines. The coupling reactions underwent at 3 mol % catalyst loading, and a large range of alcohols and amines with diverse functional groups was applied, including challenging diol and diamine. The target imine products were obtained in good to excellent yields. The present work provides an alternative method to construct highly active nonprecious metal complex catalysts based on phosphine-free ligands.
Improving C=N bond reductions with (Cyclopentadienone)iron complexes: Scope and limitations
Cettolin, Mattia,Bai, Xishan,Lübken, Dennis,Gatti, Marco,Facchini, Sofia Vailati,Piarulli, Umberto,Pignataro, Luca,Gennari, Cesare
supporting information, p. 647 - 654 (2018/10/24)
Herein, we broaden the application scope of (cyclo-pentadienone)iron complexes 1 in C=N bond reduction. The catalytic scope of pre-catalyst 1b, which is more active than the “Kn?lker complex” (1a) and other members of its family, has been expanded to the catalytic transfer hydrogenation (CTH) of a wider range of aldimines and ketimines, either pre-isolated or generated in situ. The kinetics of 1b-promoted CTH of ketimine S1 were assessed, showing a pseudo-first order profile, with TOF = 6.07 h–1 at 50 % conversion. Moreover, the chiral complex 1c and its analog 1d were employed in the enantioselective reduction of ketimines and reductive amination of ketones, giving fair to good yields and moderate enantioselectivity.
Micropores Induced Stereoselective Synthesis of E-imines: Synergistic Effect between Cerium Species and Micropores in CeAlPO-5 Molecular Sieves
Jin, Yangxin,Cao, Yali,Fang, Guoyong,Ruan, Fei,Ke, Qingping
, p. 3178 - 3181 (2019/07/04)
Metal-doped zeolitic microporous materials are often viewed as something extremely negative as catalysis for the reactions involving aromatic molecules because of severe diffusion limitation. For these reasons, many chemists aim to development of the large microporous or hierarchical micro-mesoporous zeolites as supports that allow for the access of the “bulky” reactants. But the “small” micropore with respect to an aromatic molecules-involving reaction is not always a negative point. Here we employed a hierarchical micro-mesoporous CeAlPO-5 molecular sieve (HP-CeAlPO-5) as the catalyst that can catalyze stereoselective synthesis of E-imines through the reaction of alcohols with amines. Control reactions, DFT calculations and GC-MS analyses demonstrated that the feature of the uniform “small” micropore in the HP-CeAlPO-5 catalyst play a key role in the stereoselective synthesis of E-imines. In addition, the reaction tolerates a broad range of alcohols and amines, and can be performed with as little as 0.89 mole percent catalyst in more than 90.6 percent yield and about 99.7 : 0.3 stereoselective ratio. This zeolitic catalyst provides a conceptually new and practical protocol to stereoselective synthesis of E-imine compounds.
Synergistic Photoredox Catalysis and Organocatalysis for Inverse Hydroboration of Imines
Zhou, Nengneng,Yuan, Xiang-Ai,Zhao, Yue,Xie, Jin,Zhu, Chengjian
supporting information, p. 3990 - 3994 (2018/03/21)
The first catalytic inverse hydroboration of imines with N-heterocyclic carbene (NHC) boranes has been realized by means of cooperative organocatalysis and photocatalysis. This catalytic combination provides a promising platform for promoting NHC-boryl radical chemistry under sustainable and radical-initiator-free conditions. The highly important functional-group compatibility and possible application in late-stage hydroborations represent an important step forward to an enhanced α-amino organoboron library.
Photo-induced reductive cross-coupling of aldehydes, ketones and imines with electron-deficient arenes to construct aryl substituted alcohols and amines
Liu, Zan,Nan, Xiaolei,Lei, Tao,Zhou, Chao,Wang, Yang,Liu, Wenqiang,Chen, Bin,Tung, Chenho,Wu, Lizhu
, p. 487 - 494 (2018/03/22)
Umpolung reactions of C=X bonds (X = O, N) are valuable ways of constructing new C–C bonds, which are sometimes difficult to be constructed using traditional synthetic pathways. Classical polarity inversion of C=X bonds (X = O, N) usually requires air or moisture-sensitive and strong reducing agents, which limit the feasibility of substrate scope. Herein we describe a photo-induced reductive cross-coupling reaction of aldehydes, ketones and imines with electron-deficient arenes (aromatic nitriles) using fac-Ir(ppy)3 as a photocatalyst and diisopropylethylamine (DIPEA) as a terminal reductant under visible light irradiation. Mild conditions and high yields mean that this new polarity inversion strategy can be used with aryl-substituted alcohols and amines. Spectroscopic studies and control experiments have demonstrated the oxidative quenching of Ir(ppy)3* by electron-deficient arenes involved in the key step for the C–C bond formation.
Rhodium-catalyzed synthesis of imines and esters from benzyl alcohols and nitroarenes: Change in catalyst reactivity depending on the presence or absence of the phosphine ligand
Song, Taemoon,Park, Ji Eun,Chung, Young Keun
, p. 4197 - 4203 (2018/04/14)
The [Rh(COD)Cl]2/xantphos/Cs2CO3 system efficiently catalyzes the reductive N-alkylation of aryl nitro compounds with alcohols by a borrowing-hydrogen strategy to afford the corresponding imine products in good to excellent yields. In the absence of xantphos, the [Rh(COD)Cl]2/Cs2CO3 catalytic system behaves as an effective catalyst for the dehydrogenative coupling of alcohols to esters, with nitrobenzene as a hydrogen acceptor. The reactivity of the rhodium catalytic system can be easily manipulated to selectively afford the imine or ester.
