- Continuous synthesis of peralkylated imidazoles and their transformation into ionic liquids with improved (electro)chemical stabilities
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A versatile and efficient method to synthesize tetrasubstituted imidazoles via a one-pot modified Debus-Radziszewski reaction and their subsequent transformation into the corresponding imidazolium ionic liquids is reported. The tetrasubstituted imidazoles were also synthesized by means of a continuous flow process. This straightforward synthetic procedure allows for a fast and selective synthesis of tetrasubstituted imidazoles on a large scale. The completely substituted imidazolium dicyanamide and bis(trifluoromethylsulfonyl) imide salts were obtained via a metathesis reaction of the imidazolium iodide salts. The melting points and viscosities are of the same order of magnitude as for their non-substituted analogues. In addition to the superior chemical stability of these novel ionic liquids, which allows them to be applied in strong alkaline media, the improved thermal and electrochemical stabilities of these compounds compared with conventional imidazolium ionic liquids is also demonstrated by thermogravimetrical analysis (TGA) and cyclic voltammetry (CV). Although increased substitution of the ionic liquids does not further increase thermal stability, a definite increase in cathodic stability is observable. Copyright
- Maton, Cedric,De Vos, Nils,Roman, Bart I.,Stevens, Christian V.,Vanecht, Evert,Brooks, Neil R.,Binnemans, Koen,Schaltin, Stijn,Fransaer, Jan
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- Electrochiroptical response in aqueous media: 9,10-dihydrophenanthrene-9, 10-diyl dications with Michlar's hydrol blue chromophores attached with oligoethylene glycol units
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Upon electrochemical oxidation of configurationally stable biphenyl-based electron donors (Rax)-1a and -1b to butane-1,4- diyl dications (M)-2a2+ and -2b2+, drastic changes were induced not only in UVvis but also in CD spe
- Suzuki, Takanori,Hanada, Keisuke,Katoono, Ryo,Ishigaki, Yusuke,Higasa, Sho,Higuchi, Hiroki,Kikuchi, Hirotsugu,Fujiwara, Kenshu,Yamada, Hidetoshi,Fukushima, Takanori
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- Alumina-assisted reduction of carbonyl compounds with sodium borohydride in hexane
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A broad range of aliphatic, alicyclic, and aromatic ketones and aldehydes underwent smooth reduction with a combination of common, inexpensive laboratory reagents, sodium borohydride and chromatographic neutral alumina, in hexane to afford the correspondi
- Yakabe, Shigetaka,Hirano, Masao,Morimoto, Takashi
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- Sophisticated Design of Covalent Organic Frameworks with Controllable Bimetallic Docking for a Cascade Reaction
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Precise control of the number and position of the catalytic metal ions in heterogeneous catalysts remains a big challenge. Here we synthesized a series of two-dimensional (2D) covalent organic frameworks (COFs) containing two different types of nitrogen ligands, namely imine and bipyridine, with controllable contents. For the first time, the selective coordination of the two nitrogen ligands of the 2D COFs to two different metal complexes, chloro(1,5-cyclooctadiene)rhodium(I) (Rh(COD)Cl) and palladium(II) acetate (Pd(OAc)2), has been realized using a programmed synthetic procedure. The bimetallically docked COFs showed excellent catalytic activity in a one-pot addition–oxidation cascade reaction. The high surface area, controllable metal-loading content, and predesigned active sites make them ideal candidates for their use as heterogeneous catalysts in a wide range of chemical reactions.
- Leng, Wenguang,Peng, Yongsheng,Zhang, Jianqiang,Lu, Hui,Feng, Xiao,Ge, Rile,Dong, Bin,Wang, Bo,Hu, Xiangping,Gao, Yanan
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- Adaptive N-Mesoionic Ligands Anchored to a Triazolylidene for Ruthenium-Mediated (De)Hydrogenation Catalysis
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A ruthenium cymene complex bearing a bidentate ligand composed of the N-mesoionic donor N-[1-methylpyridin-4(1H)-ylidene]amide and the C-mesoionic donor 1,2,3-triazolylidene was prepared. Spectroscopic analyses including UV-vis, electrochemical, and NMR m
- Donnelly, Kate F.,Segarra, Candela,Shao, Li-Xiong,Suen, Rachelle,Müller-Bunz, Helge,Albrecht, Martin
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- Synthesis of molecularly imprinted polymer for removal of effective impurity (benzhydrol) from diphenhydramine hydrochloride drug
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The present study describes the synthesis and preliminary testing of molecularly imprinted polymers (MIPs) as scavenger resins for removal of the genotoxic impurities (GTI) benzhydrol from active pharmaceutical ingredients (API). A new molecularly imprinted polymer was synthesized using benzhydrol (template molecule), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), 2,2′-azobisisobutironitril (intiator) and chloroform (porogenic solvent). To compare the performance of this polymer, a control polymer or non-imprinted polymer (NIP) was prepared under the same conditions without the use of template molecule. The synthesized polymers were characterized by FT-IR spectroscopy. Selectivity of the molecularly imprinted polymer for absorption benzhydrol impurities through adsorption experiments reviews and the results were compared with the adsorption of impurities by NIP. Various parameters were optimized such as time, pH, type of eluent for elution of impurities from polymer, concentration of sample and saturation of polymer. The proposed method was applied for removal of benzhydrol from Diphenhydramine hydrochloride syrup and passing it through the MIPs led to the quantitative removal of benzhydrol. The present work describes the synthesis and preliminary testing of molecularly imprinted polymers (MIPs) as scavenger resins for removal of the genotoxic impurities (GTI) benzhydrol from active pharmaceutical ingredients (API). Copyright
- Hashemi-Moghaddam, Hamid,Alaeian, Mohammad Reza
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- Kinetics of liquid-phase catalytic hydrogenation of benzophenone to benzhydrol
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Catalytic hydrogenation of benzophenone to benzhydrol was carried out in 2-propanol using Raney nickel as a catalyst at hydrogen pressures in the range of 800-2200 kPa, reaction temperatures 323-343 K, catalyst loadings 4-20 g dm-3 and benzophe
- Bawane, Sunil P.,Sawant, Sudhirprakash B.
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- Transfer hydrogenation catalysis by a N-heterocyclic carbene iridium complex on a polyoxometalate platform
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A divacant Keggin polyanion has been decorated with a N-heterocyclic carbene (NHC) iridium(I) organometallic complex to provide a molecular model of an Ir-based supported catalyst. The characterization of the hybrid compound has been performed by multinuc
- Modugno, Gloria,Monney, Angele,Bonchio, Marcella,Albrecht, Martin,Carraro, Mauro
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- Hydrosilylation of Aldehydes and Ketones Catalyzed by a 2-Iminopyrrolyl Alkyl-Manganese(II) Complex
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A well-defined and very active single-component manganese(II) catalyst system for the hydrosilylation of aldehydes and ketones is presented. First, the reaction of 5-(2,4,6-iPr3C6H2)-2-[N-(2,6-iPr2C6H3)formimino]pyrrolyl potassium (KL) and [MnCl2(Py)2] afforded the binuclear 2-iminopyrrolyl manganese(II) pyridine chloride complex [Mn2{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}2(Py)2(μ-Cl)2] 1. Subsequently, the alkylation reaction of complex 1 with LiCH2SiMe3 afforded the respective (trimethylsilyl)methyl-Mn(II) complex [Mn{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}(Py)CH2SiMe3] 2 in a good yield. Complexes 1 and 2 were characterized by elemental analysis, 1H NMR spectroscopy, Evans' method, FTIR spectroscopy, and single-crystal X-ray diffraction. While the crystal structure of complex 1 has been identified as a binuclear entity, in which the Mn(II) centers present pentacoordinate coordination spheres, that of complex 2 corresponds to a monomer with a distorted tetrahedral coordination geometry. Complex 2 proved to be a very active precatalyst for the atom-economic hydrosilylation of several aldehydes and ketones under very mild conditions, with a maximum turnover frequency of 95 min-1, via a silyl-Mn(II) mechanistic route, as asserted by a combination of experimental and theoretical efforts, the respective silanes were cleanly converted to the respective alcoholic products in high yields.
- Cruz, Tiago F. C.,Veiros, Luís F.,Gomes, Pedro T.
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p. 1195 - 1206
(2022/01/11)
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- A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen
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Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2-800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C?I, C?Br, or C?Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).
- Anwar, Muhammad,Beller, Matthias,Dastgir, Sarim,Junge, Kathrin,Leonard, David K.,Ryabchuk, Pavel
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- Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
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Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
- Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
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supporting information
p. 6169 - 6172
(2021/06/30)
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- Catalytic Aldehyde and Alcohol Arylation Reactions Facilitated by a 1,5-Diaza-3,7-diphosphacyclooctane Ligand
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We report a catalytic method to access secondary alcohols by the coupling of aryl iodides. Either aldehydes or alcohols can be used as reaction partners, making the transformation reductive or redox-neutral, respectively. The reaction is mediated by a Ni catalyst and a 1,5-diaza-3,7-diphosphacyclooctane. This P2N2ligand, which has previously been unrecognized in cross-coupling and related reactions, was found to avoid deleterious aryl halide reduction pathways that dominate with more traditional phosphines and NHCs. An interrupted carbonyl-Heck type mechanism is proposed to be operative, with a key 1,2-insertion step forging the new C-C bond and forming a nickel alkoxide that may be turned over by an alcohol reductant. The same catalyst was also found to enable synthesis of ketone products from either aldehydes or alcohols, demonstrating control over the oxidation state of both the starting materials and products.
- Isbrandt, Eric S.,Nasim, Amrah,Newman, Stephen G.,Zhao, Karen
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supporting information
p. 14646 - 14656
(2021/09/18)
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- Standardization and Control of Grignard Reactions in a Universal Chemical Synthesis Machine using online NMR
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A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements.
- Angelone, Davide,Bornemann-Pfeiffer, Martin,Cronin, Leroy,Emmerling, Franziska,Kern, Simon,Leonov, Artem,Meyer, Klas,Wolf, Jakob
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supporting information
p. 23202 - 23206
(2021/08/09)
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- Intercepting a transient non-hemic pyridine: N -oxide Fe(iii) species involved in OAT reactions
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In the context of bioinspired OAT catalysis, we developed a tetradentate dipyrrinpyridine ligand, a hybrid of hemic and non-hemic models. The catalytic activity of the iron(iii) derivative was investigated in the presence of iodosylbenzene. Unexpectedly, MS, EPR, M?ssbauer, UV-visible and FTIR spectroscopic signatures supported by DFT calculations provide convincing evidence for the involvement of a relevant FeIII-O-NPy active intermediate. This journal is
- Vo, Nhat Tam,Herrero, Christian,Guillot, Régis,Inceoglu, Tanya,Leibl, Winfried,Clémancey, Martin,Dubourdeaux, Patrick,Blondin, Geneviève,Aukauloo, Ally,Sircoglou, Marie
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supporting information
p. 12836 - 12839
(2021/12/10)
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- Site-selective D2O-mediated deuteration of diaryl alcoholsviaquantum dots photocatalysis
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Owing to the high synthetic value of deuteration in the pharmaceutical industry, we describe herein the conversion of a range of aromatic ketones to deuterium-labeled products in good to excellent yields. Efficient and site-selective deuteration of benzyl alcohols by D2O with visible light irradiation of quantum dots (QDs), together with gram-scale synthesis and photocatalyst recycling experiments indicated the potential of the developed method in practical organic synthesis.
- Li, Xu-Bing,Nan, Xiao-Lei,Tung, Chen-Ho,Wang, Yao,Wu, Li-Zhu
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supporting information
p. 6768 - 6771
(2021/07/13)
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- Tunable System for Electrochemical Reduction of Ketones and Phthalimides
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Herein, we report an efficient, tunable system for electrochemical reduction of ketones and phthalimides at room temperature without the need for stoichiometric external reductants. By utilizing NaN3 as the electrolyte and graphite felt as both the cathode and the anode, we were able to selectively reduce the carbonyl groups of the substrates to alcohols, pinacols, or methylene groups by judiciously choosing the solvent and an acidic additive. The reaction conditions were compatible with a diverse array of functional groups, and phthalimides could undergo one-pot reductive cyclization to afford products with indolizidine scaffolds. Mechanistic studies showed that the reactions involved electron, proton, and hydrogen atom transfers. Importantly, an N3/HN3 cycle operated as a hydrogen atom shuttle, which was critical for reduction of the carbonyl groups to methylene groups.
- Chen, Gong,Qiao, Tianjiao,Wang, Yaxin,Zhang, Jian,Zhao, Jianyou
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supporting information
p. 3297 - 3302
(2021/10/14)
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- Enhanced catalytic activity of one-dimensional CdS @TiO2 core-shell nanocomposites for selective organic transformations under visible LED irradiation
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In this study, we are interested in the photocatalytic activity under visible LED irradiation of one- dimensional (1D) CdS @TiO2 core–shell nanocomposites (CSNs) prepared through a facile and convenient method. For the synthesis of 1D CdS@TiO2 core/shell structure, titania source (Tetrabutyl titanate) was hydrolyzed by water vapor transmission on the surface of CdS nanowires (NWs) which were prepared via solvothermal method. The characterization of 1D CdS@TiO2 core–shell nanocomposites (CdS@TiO2 CSNs) was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, and UV–Vis diffuse reflectance spectroscopy (DRS). The as-synthesized sample was utilized for the selective reduction of nitro compounds to benzimidazole and anilide, and also the reduction of benzophenones to alcohol under blue LED irradiation. The 1D CdS@TiO2 CSNs exhibited enhanced photoactivity compared with the pure TiO2, CdS nanowires and commercial TiO2-P25. The excellent reusability of the photocatalyst was examined for six runs. The results demonstrated that the prepared sample has the potential to provide a promising visible light-driven photocatalyst for other organic transformations.
- Eskandari, Parvin,Kazemi, Foad,Ramdar, Moosa,Zand, Zahra
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- Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
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Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
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supporting information
p. 9029 - 9039
(2021/06/28)
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- Carbon monoxide-driven osmium catalyzed reductive amination harvesting WGSR power
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Herein, we present the first example of Os-catalyzed efficient reductive amination under water-gas shift reaction conditions. The developed catalytic systems are formedin situin aqueous solutions, employ as small as 0.0625 mol% osmium and are capable of delivering reductive amination products for a broad range of aliphatic and aromatic carbonyl compounds and amines. The scope of the reaction, active catalytic systems, possible limitations of the method and DFT-supported mechanistic considerations are discussed in detail in the manuscript.
- Afanasyev, Oleg I.,Biriukov, Klim O.,Chusov, Denis,Godovikova, Maria,Loginov, Dmitry A.,Nelyubina, Yulia V.,Tsygankov, Alexey A.,Vasilyev, Dmitry V.,Vinogradov, Mikhail M.
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p. 4922 - 4930
(2021/07/26)
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- Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
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We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
- Topf, Christoph,Vielhaber, Thomas
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- Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
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Reduction reactions of unsaturated compounds are fundamental transformations in synthetic chemistry. In this context, the reduction of polarized double bonds such as carbonyl or C=C motifs can be achieved by hydrogenation reactions. We describe here a highly chemoselective Mn(I)-based PNP pincer catalyst for the hydrosilylation of aldehydes and ketones employing polymethylhydrosiloxane (PMHS) as inexpensive hydrogen donor. Graphic abstract: [Figure not available: see fulltext.]
- Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
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p. 635 - 639
(2021/06/17)
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- Melamine-Based Porous Organic Polymers Supported Pd(II)-Catalyzed Addition of Arylboronic Acids to Aromatic Aldehydes
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Abstract: A new type melamine-based porous organic polymers (SZU-1) has been synthesized with melamine and 2,2′-bipyridyl-5,5′-dialdehyde by a one-pot method and fully characterized. Divalent palladium salts were coordinated to this polymer network which successfully catalyzed the nucleophilic addition reaction of arylboronic acids to aromatic aldehydes. With only 1.0?mol% heterogeneous catalyst loading, high reaction yields (>?85%) can be achieved in most cases. The scope of substrates was also investigated and the catalyst showed universal applicability. Graphic Abstract: The loose and porous melamine-based porous organic polymers (SZU-1) are synthesized by melamine and 2,2′-bipyridyl-5,5′-dialdehyde. The performance of SZU-1 was characterized and most of the substrates achieved high yield (> 85%) in the catalytic performance test.[Figure not available: see fulltext.]
- Shen, Kai,Wen, Min,Fan, Chaogang,Lin, Shaohui,Pan, Qinmin
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p. 2612 - 2621
(2021/01/15)
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- Pincerlike molybdenum complex and preparation method thereof, catalytic composition and application thereof, and alcohol preparation method
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The invention discloses a clamp-type molybdenum complex, a preparation method, a corresponding catalyst composition and application. The method comprises the steps: obtaining 9 molybdenum complexes with different structures through coordination reaction of 2-(substituent ethyl)-(5, 6, 7, 8-tetrahydroquinolyl) amine and a corresponding carbonyl molybdenum metal precursor; and catalyzing a ketone compound transfer hydrogenation reaction through a molybdenum complex to generate 40 alcohol compounds. The preparation method of the molybdenum complex is simple, high in yield and good in stability. For a transfer hydrogenation reaction of ketone, the molybdenum-based catalytic system has high catalytic activity and small molybdenum loading capacity, is used for production of aromatic and aliphatic alcohols, and has the advantages of simple method, small environmental pollution and high yield.
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Paragraph 0125-0132
(2021/08/11)
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- Synthesis of 1-Pyrroline by Denitrogenative Ring Expansion of Cyclobutyl Azides under Thermal Conditions
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We herein report an efficient and systematic synthesis of 1-pyrrolines from cyclobutyl azides under thermal and neutral conditions. The reaction proceeded without any additional reagents, and nitrogen was generated as the sole by-product. Furthermore, the generated 1-pyrrolines could be continuously transformed into pyrroles, N-Boc-amines, and oxaziridines in an one-pot manner. (Figure presented.).
- Ban, Kazuho,Miki, Yuya,Sajiki, Hironao,Sawama, Yoshinari,Tomita, Naohito
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supporting information
p. 3481 - 3484
(2021/06/17)
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- CeO2-nanocubes as efficient and selective catalysts for the hydroboration of carbonyl groups
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The CeO2-nanoparticle catalysed hydroboration of carbonyl compounds with HBpin (pin = OCMe2CMe2O) is reported to afford the corresponding borate esters in excellent yield. A series of aromatic and aliphatic aldehydes and ketones having synthetically important functional groups were well-Tolerated under mild reaction conditions. Further, chemoselective hydroboration of aldehydes over other reducible functional groups such as ketone, nitrile, hydroxide, alkene, alkyne, amide, ester, nitro, and halides was achieved. Importantly the catalyst can be recycled up to ten runs with slight loss in activity. This journal is
- Bhawar, Ramesh,Bose, Shubhankar Kumar,Patil, Kiran S.
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supporting information
p. 15028 - 15034
(2021/09/04)
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- Polyoxometalate-Incorporated Framework as a Heterogeneous Catalyst for Selective Oxidation of C-H Bonds of Alkylbenzenes
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Developing new catalysts for highly efficient and selective oxidation of saturated C-H bonds is significant due to their thermodynamic strength. Via incorporation of PW12O403-, pyridine-2,5-dicarboxylic acids (pydc), and Fe(III) ions into one framework, a new polyoxometalate-based metal-organic framework, [HFe4O2(H2O)4(pydc)3PW12O40]·10.5H2O (FeW-PYDC), was successfully prepared by a hydrothermal method. Interestingly, FeW-PYDC features a three-dimensional porous structure with {Fe4O2} interconnecting with PW12O403- units. FeW-PYDC displayed excellent performance in the selective oxidation of C-H bonds of alkylbenzenes with high conversion (95.7%) and selectivity (96.6%). As an effective heterogeneous catalyst, FeW-PYDC demonstrates good reusability and structural stability.
- Hu, Xin,Ma, Pengtao,Niu, Jingyang,Wang, Hui,Wang, Jingping,Wang, Quanzhong,Wang, Yingyue,Xu, Baijie
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p. 7753 - 7761
(2021/06/27)
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- Regio- And Trans-Selective Ni-Catalyzed Coupling of Butadiene, Carbonyls, and Arylboronic Acids to Homoallylic Alcohols under Base-Free Conditions
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We herein report a Ni-catalyzed three-component coupling of 1,3-butadiene, carbonyl compounds, and arylboronic acids as a general synthetic approach to 1,4-disubstituted homoallylic alcohols, an important class of compounds, which have previously not been straightforward to access. The reaction occurs efficiently using a Ni(cod)2 catalyst without any external base and ligand at ambient temperature and allows a highly regioselective and trans-selective 1,4-dicarbofunctionalization of feedstock butadiene in a single operation. This simple and practical protocol could apply to a comprehensive scope of substrates. The neutral conditions show extraordinary tolerance for even highly base-sensitive functional groups.
- Li, Yu-Qing,Chen, Guang,Shi, Shi-Liang
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supporting information
p. 2571 - 2577
(2021/04/05)
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- Hetero- A nd Homobimetallic Complexes Bridged by a Bis(NHC) Ligand: Synthesis via Selective Sequential Metalation and Catalytic Applications in Tandem Organic Transformations
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A (bis)azolium salt [L1-H2]Br2 (5), synthesized following multistep procedures, was realized to be a suitable platform for accessing the bis(NHC) ligand supported heterobimetallic IrIII-M (M = PdII/AuI) complexes via a sequential metalation strategy for their potential catalytic applications in one-pot tandem organic transformations. First, the reaction of 5 with 0.5 equiv of [Ir(Cp-)Cl2]2 selectively yielded a monometallic IrIII complex 6, which was further metalated using Pd(OAc)2/NaOAc to afford the heterobimetallic IrIII-PdII complex 7. On the other hand, complex 6 was reacted with Ag2O, followed by transmetalation with [Au(SMe2)Cl] in a one-pot manner, to yield the IrIII-AuI complex 8. Further, the related homobimetallic IrIII and PdII complexes 9 and 10, respectively, have also been synthesized directly from [L1-H2]Br2. All the homo/heterobimetallic complexes have been well-characterized by multinuclear NMR spectroscopy, ESI-mass spectrometry, and via single-crystal X-ray diffraction studies of the complexes 7, 8, and 10. The heterobimetallic IrIII-PdII complex 7 has been tested as a catalyst for three one-pot tandem catalytic reactions: (a) Suzuki-Miyaura coupling and transfer hydrogenation of ketones, (b) hydrodefluorination and transfer hydrogenation of ketones, and (c) hydrodehalogenation and transfer hydrogenation of imines. Importantly, the catalytic activity of heterobimetallic complex 7 in the above-mentioned reactions was found to be better than the mixture of their corresponding homobimetallic counterparts 9 and 10, keeping the concentration of the metal centers constant. These observations affirm some sort of cooperativity between the two metal centers (Ir and Pd) connected via a single ligand frame in 7 when catalytic activity is concerned, which thus constitutes a superior catalytic system than that of the cases where two separate metal complexes (hence, the two metal centers are not connected by a single ligand framework) are used.
- Nishad, Rajeev C.,Kumar, Shashi,Rit, Arnab
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p. 915 - 926
(2021/05/04)
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- Sodium Aminodiboranate, a New Reagent for Chemoselective Reduction of Aldehydes and Ketones to Alcohols
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Sodium aminodiboranate (NaNH 2(BH 3) 2, NaADBH) is a new member of the old borane family, which exhibits superior performance in chemoselective reduction. Experimental results show that NaADBH can rapidly reduce aldehydes and ketones to the corresponding alcohols in high efficiency and selectivity under mild conditions. There are little steric and electronic effects on this reduction.
- Wang, Jin,Guo, Yu,Li, Shouhu,Chen, Xuenian
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supporting information
p. 1104 - 1108
(2021/05/25)
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- Formation of a hydride containing amido-zincate using pinacolborane
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Amido-zincates containing hydrides are underexplored yet potentially useful complexes. Attempts to access this type of zincate through combining amido-organo zincates and pinacolborane (HBPin)viaZn-C/H-BPin exchange led instead to preferential formation of amide-BPin and/or [amide-BPin(Y)]?(Y = Ph, amide, H), when the amide is hexamethyldisilazide or 2,2,6,6-tetramethylpiperidide and the hydrocarbyl group was phenyl or ethyl. In contrast, the use of a dipyridylamide (dpa) based arylzinc complex led to Zn-C/H-BPin metathesis being the major outcome. Independent synthesis and full characterisation of two LnLi[(dpa)ZnPh2] (L = THF,n= 3; L = PMDETA,n= 1) complexes,1and3, respectively, enabled reactivity studies that demonstrated that these species display zincate type reactivity (by comparison to the lower reactivity of the neutral complex (Me-dpa)ZnPh2,4, Me-dpa = 2,2′-dipyridyl-N-methylamine). This included1performing the rapid deprotonation of 4-ethynyltoluene and also phenyl transfer to α,α,α-trifluoroacetophenone in contrast to neutral complex4. Complex1reacted with one equivalent of HBPin to give predominantly PhBPin (ca.90%) and a lithium amidophenylzincate containing a hydride unit, complex7-A, as the major zinc containing product. Complex7-Atransfers hydride to an electrophile preferentially over phenyl, indicating it reacts as a hydridozincate. Attempts to react1with >1 equivalent of HBPin or with catecholborane led to more complex outcomes, which included significant borane and dpaZn substituent scrambling, two examples of which were crystallographically characterised. While this work provides proof of principle for Zn-C/H-BPin exchange as a route to form an amido-zincate containing a hydride, amido-organozincates that undergo more selective Zn-C/H-BPin exchange still are required.
- Ingleson, Michael J.,Nichol, Gary S.,Uzelac, Marina,Yuan, Kang
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supporting information
p. 14018 - 14026
(2021/10/19)
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- Photo-induced phosphorus radical involved semipinacol rearrangement reaction: Highly synthesis of γ-oxo-phosphonates
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Hydroxyphosphoric acids display the unique biological activities, and they have some attractive prospects as clinical drug moleculars. Herein, a new approach for the synthesis of γ-oxo-phosphonates (the precursor of hydroxyphosphoric acid) has been established through the semipinacol rearrangement tactic involved the photo-induced phosphorus radical process. Most important, this transformation is avoid of the external oxidants, and occurs very well under the sunlight irradiation, meanwhile the γ-oxo-phosphonate was easily derivatized to obtain γ-hydroxyphosphoric acid, thus highlights the synthesis value of this method.
- Wang, Chunhai,Huang, Xiaoling,Liu, Xueting,Gao, Suqian,Zhao, Bin,Yang, Shangdong
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supporting information
p. 677 - 680
(2019/08/27)
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- A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
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A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
- Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
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p. 5019 - 5026
(2020/05/01)
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- Phenylene-bridged bis(benzimidazolium) (BBIm2+): a dicationic organic photoredox catalyst
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A dicationic photoredox catalyst composed of phenylene-bridged bis(benzimidazolium) (BBIm2+) was designed, synthesised and demonstrated to promote the photochemical decarboxylative hydroxylation and dimerisation of carboxylic acids. The catalytic activity of BBIm2+ was higher than that for a monocation analogue, suggesting that the dicationic nature of BBIm2+ plays a key role in these decarboxylative reactions. The rate constant for the decay of the triplet-triplet absorption of the excited BBIm2+ increased with increasing concentration of the carboxylate anion with a saturated dependence, suggesting that photoinduced electron transfer occurs within the ion pair complex composed of the triplet excited state of BBIm2+ and a carboxylate anion.
- Kodama, Takuya,Kubo, Maiko,Shinji, Wataru,Ohkubo, Kei,Tobisu, Mamoru
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p. 12109 - 12117
(2020/11/27)
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- 9,10-Dihydroanthracene auto-photooxidation efficiently triggered photo-catalytic oxidation of organic compounds by molecular oxygen under visible light
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The development of mild and efficient process for the selective oxidation of organic compounds by molecular oxygen (O2) can be one of the key technologies for synthesizing oxygenates. This paper discloses an efficient and mild synthesis protocol for the O2-involved ethylbenzene (EB) photooxidation triggered by 910-dihydroanthracene (DHA) auto- photooxidation in acetone under visible light illumination, which can achieve 87.7 percent EB conversion and 99.5 percent acetylacetone (ACP) selectivity under ambient conditions. Also, 62.9 percent EB conversion and 96.3 percent ACP selectivity is obtained in air atmosphere. Furthermore, this protocol has a good adaptability for the photooxidation of other organic substrates such as tetrahydronaphthalene, diphenylmethane, toluene, cyclohexane, cyclohexene, alcohol, methylfuran and thioether to their corresponding oxygenates. A series of control and quenching tests, combined with EPR spectra, suggest that the photo-excited DHA can transfer its photo-electron to O2 to yield a superoxide radical anion (O2??), then DHA is preferentially oxidized to anthraquinone (AQ) by the active O2?? owing to its high reactivity. Finally, the in situ generated AQ as an active photo-catalyst can achieve the photooxidation of EB and other organic compounds by O2. The present photo-autoxidation protocol gives a good example for the O2-based selective oxidation of inert hydrocarbons under mild conditions.
- Chen, Mengke,Deng, Youer,Fu, Zaihui,Hu, Wenwei,Jiang, Dabo,Liu, Yachun,Mao, Feng,Su, Anqun,Yang, Bo,Zhang, Chao
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- Ruthenium(II) complexes with pyridine-based Schiff base ligands: Synthesis, structural characterization and catalytic hydrogenation of ketones
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This study investigated the synthesis and characterization of which the result of the reaction of Schiff base ligands containing pyridine with [RuCl2(p-cymene)]2. The spectroscopic techniques used for the characterization process wer
- Buldurun, Kenan,?zdemir, Metin
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- Method for preparing alcohol compounds through hydrogenation reduction of ketone and aldehyde
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The invention belongs to the technical field of medical and natural compound chemical intermediates and related chemistry, and provides a method for preparing alcohol compounds through a hydrogenationreduction of ketone and aldehyde. Ketone, aldehyde and derivatives thereof, which are used as raw materials, are subjected to hydrogenation reduction with nano-porous palladium as a catalyst and hydrogen as a hydrogen source, wherein the pressure of hydrogen is 0.1-0.5 MPa, the molar concentration of the ketone, aldehyde and derivatives thereof in the solvent is 0.01-2 mmol/m, the pore skeleton size of the adopted catalyst is 1-50 nm, and the molar ratio of ketone, aldehyde and derivatives thereof to the catalyst is 1:0.01 to 1:0.5. The method has the advantages of high product yield, very mild reaction conditions, simplicity in operation and post-treatment, good repeatability of the catalyst, no obvious reduction of the catalytic effect after the catalyst is used for many times, and provision of the possibility for industrialization.
- -
-
Paragraph 0060-0064
(2020/02/14)
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- Reduced graphene oxide/iron oxide hybrid composite material as an efficient magnetically separable heterogeneous catalyst for transfer hydrogenation of ketones
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Reduced graphene oxide was synthesized and functionalized with FeSO4?7H2O to form a reduced graphene oxide/iron oxide hybrid composite. The hybrid composite was extensively characterized using various techniques. Its application for transfer hydrogenation of various ketones was studied. The investigation showed that it serves as a good catalyst for transfer hydrogenation of aromatic and some aliphatic ketones resulting in excellent isolated yields (97–99%) of products. It is magnetically separable showing good reusability. The products were characterized and compared with authentic ones.
- Borah, Geetika,Bordoloi, Shreemoyee,Gogoi, Pradip K.,Konwer, Surajit,Sultana, Samim
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- Efficient Transfer Hydrogenation of Ketones using Methanol as Liquid Organic Hydrogen Carrier
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Herein, we demonstrate an efficient protocol for transfer hydrogenation of ketones using methanol as practical and useful liquid organic hydrogen carrier (LOHC) under Ir(III) catalysis. Various ketones, including electron-rich/electron-poor aromatic ketones, heteroaromatic and aliphatic ketones, have been efficiently reduced into their corresponding alcohols. Chemoselective reduction of ketones was established in the presence of various other reducible functional groups under mild conditions.
- Garg, Nidhi,Paira, Soumen,Sundararaju, Basker
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p. 3472 - 3476
(2020/05/29)
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- Transfer hydrogenation of aldehydes and ketones catalyzed using an aminophosphinite POCNHpincer complex of Ni(ii)
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The aminophosphinite pincer complex (POCNH)NiBr was found to effectively catalyze the transfer hydrogenation of aldehydes and ketones with 2-propanol and KOtBu as a base, presenting a rare example of bifunctional nickel transfer hydrogenation catalysts. The transfer hydrogenation of aldehydes and ketones was found to be selective, tolerating a wide range of other functional groups, including those prone to reduction, such as esters, amides, alkenes, pyridines, and nitriles. The reactions were suggested to proceedviathe metal-ligand cooperative mechanism with an intermediacy of an amido (POCN)NiIIspecies.
- ?ztop?u, ?zgür,Hayrapetyan, Davit,Khalimon, Andrey Y.,Lyssenko, Konstantin A.,Segizbayev, Medet,Shakhman, Dinmukhamed
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supporting information
p. 11950 - 11957
(2020/09/21)
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- Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
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We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
- Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
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supporting information
(2020/03/25)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Diarylmethanols synthesis by nickel(II)-catalyzed addition of arylboronic acids to aryl aldehydes
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A practical procedure for the addition of arylboronic acids to aromatic aldehydes has been developed in the presence of NiCl2(PPh3)2/1,3-bis-(2,6-diisopropylphenyl)imidazolium chloride (IPr·HCl) system with good yield. Generally, electron-rich and-neutral aryl aldehydes showed excellent reactivity and provided desired products in high yields. This procedure will provide new way to the synthesis of diarylmethanols.
- Bie, Fusheng,Cao, Han,Cui, Haizhu,Li, Tang,Liu, Xuejing,Ma, Jie,Wang, Meng
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supporting information
p. 248 - 253
(2020/04/24)
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- Rediscovering aminal chemistry: Copper(ii) catalysed formation under mild conditions
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Aminals, the N,N analogues of acetals, have been thoroughly explored in organic chemistry, with a particular focus on heteroaromatic aldehyde lithiation. Nevertheless, the existing methodologies for their formation typically employ harsh conditions limiting their usefulness. In this work, we present an efficient and mild methodology for the preparation of aminals from aromatic aldehydes, including furanic platforms. These mild conditions allowed ease of access to a plethora of aminals and as such we set out to explore previously unaccessible potential applications. By studying the stability of various aminals, we were able to develop a simple aldehyde protecting group based on a commercial diamine which is deprotected under mind conditions. We developed a protocol for the scavenging of genotoxic aldehydes by taking advantage of our methodology and a diamine resin, as well as early studies on the development of a stimuli-responsive release system using a salycil aldehyde derived aminal. This journal is
- Afonso, Carlos A. M.,António, Jo?o P. M.,Gomes, Rafael F. A.,Mendon?a, Ricardo,Pereira, Juliana G.
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supporting information
p. 7484 - 7490
(2020/11/18)
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- 1-D manganese(ii)-terpyridine coordination polymers as precatalysts for hydrofunctionalisation of carbonyl compounds
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Reductive catalysis with earth-abundant metals is currently of increasing importance and shows potential in replacing precious metal catalysis. In this work, we revealed catalytic hydroboration and hydrosilylation of ketones and aldehydes achieved by a structurally defined manganese(ii) coordination polymer (CP) as a precatalyst under mild conditions. The manganese-catalysed methodology can be applied to a range of functionalized aldehydes and ketones with turnover numbers (TON) of up to 990. Preliminary results on the regioselective catalytic hydrofunctionalization of styrenes by the Mn-CP catalyst are also presented.
- Johnson, Jahvon,Li, Sihan,Mo, Zixuan,Neary, Michelle C.,Zeng, Haisu,Zhang, Guoqi,Zheng, Shengping
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supporting information
p. 2610 - 2615
(2020/03/05)
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- Erratum: Redox-Noninnocent Ligand-Supported Vanadium Catalysts for the Chemoselective Reduction of C=X (X = O, N) Functionalities (Journal of the American Chemical Society (2019) 141:38 (15230-15239) DOI: 10.1021/jacs.9b07062)
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Pages 15232, 15233, and 15236. In the original paper, the doublet wave functions for 21 and 21a/21b were incorrectly (Figure Presented). reported as spin-contaminated in sections 2.3 and 2.8 (Figure 3 and Scheme 9, respectively.) This comes from the incorrectly reported expected eigenvalue of 0.75 for the spin-squared operator ??2? for the antiferromagnetically coupled doublet |↓?L|↑↑?V state (originally given in the Supporting Information). The correct expected eigenvalue for the |↓?L|↑↑?V state should be 1.75. The wave functions for 21 and 21a/21b (eigenvalues 1.79 and 1.77/1.66, respectively) are therefore not spincontaminated. The corrected Figure 3 and Scheme 9 are presented below. A corrected Supporting Information file is also provided. The corrections do not affect any of the conclusions of the Article, but slightly decrease the gap between the quartet and doublet spin surfaces. Scheme 3 has been also corrected to reflect the fact that (CH3)3SiCH2 ? radicals can only react based on spin conservation.
- Zhang, Guoqi,Wu, Jing,Zheng, Shengping,Neary, Michelle C.,Mao, Jincheng,Flores, Marco,Trovitch, Ryan J.,Dub, Pavel A.
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supporting information
p. 16507 - 16509
(2020/10/14)
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- Potassium Fluoride-Catalyzed Hydroboration of Aldehydes and Ketones: Facile Reduction to Primary and Secondary Alcohols
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A catalytic hydroboration of various ketones and aldehydes can be achieved in the presence of inexpensive and commercially available inorganic salts containing fluoride anion. As a result, the reduction of carbonyl moieties to the corresponding primary and secondary alcohols can be achieved at room temperature under mild conditions.
- Kuciński, Krzysztof,Hreczycho, Grzegorz
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supporting information
p. 552 - 555
(2020/02/04)
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- Palladium-Catalyzed Selective Reduction of Carbonyl Compounds
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Two new examples of structurally characterized β-diketiminate analogues i.e., conjugated bis-guanidinate (CBG) supported palladium(II) complexes, [LPdX]2; [L= {(ArHN)(ArN)–C=N–C=(NAr)(NHAr)}; Ar = 2,6-Et2-C6H3], X = Cl (1), Br (2) have been reported. The synthesis of complexes 1–2 was achieved by two methods. Method A involves deprotonation of LH by nBuLi followed by the treatment of LLi (insitu formed) with PdCl2 in THF, which afforded compound 1 in good yield (75 %). In Method B, the reaction between free LH and PdX2 (X = Cl or Br) in THF allowed the formation of complexes 1 (Yield 73 %) and 2 (Yield 52 %), respectively. Moreover, these complexes were characterized thoroughly by several spectroscopic techniques (1H, 13C NMR, UV/Vis, FT-IR, and HRMS), including single-crystal X-ray structural and elemental analyses. In addition, we tested the catalytic activity of these complexes 1–2 for the hydroboration of carbonyl compounds with pinacolborane (HBpin). We observed that compound 1 exhibits superior catalytic activity when compared to 2. Compound 1 efficiently catalyzes various aldehydes and ketones under solvent-free conditions. Furthermore, both inter- and intramolecular chemoselectivity hydroboration of aldehydes over other functionalities have been established.
- Sarkar, Nabin,Mahato, Mamata,Nembenna, Sharanappa
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p. 2295 - 2301
(2020/05/18)
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- Lithium Bromide/HBpin: A Mild and Effective Catalytic System for the Selective Hydroboration of Aldehydes and Ketones
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The catalytic hydroboration of aldehydes and ketones with HBpin was examined using simple and commercially available metal salts (Li, Na, and K). Among the tested salts, LiBr (0.5–1.0 mol%) was found to be an efficient catalyst for the hydroboration of various aldehydes and ketones at room temperature. Further, the chemoselective hydroboration of aldehydes over ketones was also demonstrated.
- An, Duk Keun,Choi, Hyeon Seong,Hwang, Hyonseok,Kim, Hanbi,Lee, Ji Hye,Shin, Hye Lim,Yi, Jaeeun
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p. 1009 - 1018
(2020/10/12)
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- Low-valence anionic α-diimine iron complexes: Synthesis, characterization, and catalytic hydroboration studies
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The synthesis of rare anionic heteroleptic and homoleptic α-diimine iron complexes is described. Heteroleptic BIAN (bis(aryl)iminoacenaphthene) complexes 1-[K([18]c-6)-(thf)0.5] and 2-[K([18]c-6)(thf)2] were synthesized by reduction of the [(BIAN)FeBr2] precursor complex using stoichiometric amounts of potassium graphite in the presence of the corresponding olefin. The electronic structure of these paramagnetic species was investigated by numerous spectroscopic analyses (NMR, EPR, 57Fe M?ssbauer, UV-vis), magnetic measurements (Evans NMR method, SQUID), and theoretical techniques (DFT, CASSCF). Whereas anion 1 is a low-spin complex, anion 2 consists of an intermediate-spin Fe(III) center. Both complexes are efficient precatalysts for the hydroboration of carbonyl compounds under mild reaction conditions. The reaction of bis(anthracene) ferrate(1-) gave the homoleptic BIAN complex 3-[K([18]c-6)(thf)], which is less catalytically active. The electronic structure was elucidated with the same techniques as described for complexes 1-[K([18]c-6)(thf)0.5] and 2-[K([18]c-6)(thf)2] and revealed an Fe(II) species in a quartet ground state.
- Bodensteiner, Michael,Coburger, Peter,Demeshko, Serhiy,Gawron, Martin,Maier, Thomas M.,Meyer, Franc,Wolf, Robert,de Bruin, Bas,van Leest, Nicolaas P.
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p. 16035 - 16052
(2020/11/20)
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- One-pot method for the synthesis of 1-aryl-2-aminoalkanol derivatives from the corresponding amides or nitriles
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We have identified a novel one-pot method for the synthesis of β-amino alcohols, which is based on C-H bond hydroxylation at the benzylic α-carbon atom with a subsequent nitrile or amide functional group reduction. This cascade process uses molecular oxygen as an oxidant and sodium bis(2-methoxyethoxy)aluminum hydride as a reductant. The substrate scope was examined on 30 entries and, although the respective products were provided in moderate yields only, the above simple protocol may serve as a direct and powerful entry to the sterically congested 1,2-amino alcohols that are difficult to prepare by other routes. The plausible mechanistic rationale for the observed results is given and the reaction was applied to a synthesis of a potentially bioactive target. This journal is
- Bobal, Pavel,Otevrel, Jan,Svestka, David
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p. 25029 - 25045
(2020/07/14)
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- Transfer hydrogenation via generation of hydride intermediate and base-free alcohol oxidation activity studies on designed ruthenium complexes derived from NNN pincer type ligands
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Ruthenium complexes(1–3) have been synthesized using pincer-type ligands L1 = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)pyridine, L2 = (E)-2-(1-phenyl-2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)pyridine, L3 = (E)-2-(phenyl(2-phenyl-2-(pyridin-2-yl)hydrazono) methyl)pyridine. The molecular structures of all the complexes 1, 2 and 3 were determined by using single crystal X-ray diffraction. These complexes showed excellent catalytic activities such as transfer hydrogenation and alcohol oxidation. Theoretical calculations have been performed to understand the electronic properties of all the complexes using B3LYP as a function and LANL2DZ as a basis set.
- Singh, Prasoon Raj,Maji, Ankur,Singh, Ovender,Singh, Udai P.,Ghosh, Kaushik
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- Benzyl C–O and C–N Bond Construction via C–C Bond Dissociation of Oxime Ester under Visible Light Irradiation
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A photoredox benzyl activation was developed via formidable C(sp3)–C(sp3) bond dissociation of 1-aryl acetone oxime esters, which were easily prepared from benzyl ketones. Further coupling with O- and N- nucleophiles successfully forged important benzyl ether and amines derivatives in one pot. In this process, different substitutions on oxime esters were found compatible and various primary and secondary alcohols and amines, as well as amides showed good performance as nucleophiles. Mechanistic studies by control experiments, electrochemical measurements and in-situ NMR spectra proposed a N–O bond interruption/C–C bond fragmentation/oxidation sequence to provide the key cation intermediate for the next electrophilic SN process. The features of mild condition, short reaction time and broad substrate scope made this new strategy much promising in the transformation of benzyl compounds, which might be valuable in last-stage functionalizations.
- Fan, Xiuwei,Lei, Tao,Liu, Zan,Yang, Xiu-Long,Cheng, Yuan-Yuan,Liang, Ge,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 1551 - 1558
(2019/09/09)
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- Cu(i) complex bearing a PNP-pincer-Type phosphaalkene ligand with a bulky fused-ring Eind group: Properties and applications to FLP-Type bond activation and catalytic CO2 reduction
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Herein, we report the synthesis of [Cu(Eind2-BPEP)][PF6] (2) (Eind2-BPEP = 2,6-bis(2-Eind-2-phosphaethenyl)pyridine, Eind = 1,1,3,3,5,5,7,7-octaethyl-1,2,3,5,6,7-hexahydro-s-indacen-4-yl), a three-coordinated Cu(i) complex bearing a PNP-pincer-Type phosphaalkene ligand with bulky fused-ring Eind groups. The Gutmann-Beckett test revealed that complex 2 is highly Lewis acidic and comparable in strength to B(C6F5)3, which is a relatively strong Lewis acid. In addition, 2 is more Lewis acidic than [Cu(Mes?2-BPEP)][PF6] (3), the analogous complex with less-bulky Mes? instead of Eind groups. DFT calculations using model compounds revealed that the higher Lewis acidity of 2 compared to 3 is not due to the electronic effects of the ligand, but due to a reduction in the LUMO energy caused by the steric effect of the bulky Eind groups. When combined with a tertiary amine, the highly Lewis acidic and bulky 2 exhibits the reactivity of a frustrated Lewis pair (FLP) and can activate hydrogen and phenylacetylene. Complexes 2 and 3 were found to catalyze the hydrogenation and hydrosilylation of CO2 in the presence of DBU under relatively mild conditions.
- Choi, Jun-Chul,Ozawa, Fumiyuki,Takeuchi, Katsuhiko,Tanaka, Yuto,Tanigawa, Ippei
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p. 3630 - 3637
(2020/04/02)
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- Fe(III)-Catalyzed, Cyclizative Coupling between 2-Alkynylbenzoates and Carbinols: Rapid Generation of Polycyclic Isocoumarins and Phthalides and Mechanistic Study
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FeCl3 catalyzed, highly regioselective cyclizative coupling of internal alkynes with alcohols has been reported for the rapid synthesis of structurally divergent, complex isocoumarins and phthalides respectively in intermolecular and intramolecular fashion. This strategy exhibited very high substrate scope and efficiency and proceeds through the simultaneous formation of C?O and C?C bonds. Observations from a series of control experiments supported a) the mechanism as Lewis acid catalyzed dual activation of ester and alcohol, b) the role of carbocation for the enhanced rates of cyclization, i. e., activation of alkyne by carbocation, and c) no role of HCl in the reported cascade process. (Figure presented.).
- Gandhi, Soniya,Baire, Beeraiah
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p. 2651 - 2657
(2020/05/25)
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- α-Lithiobenzyloxy as a Directed Metalation Group in ortho-Lithiation Reactions
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The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila(germa)dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
- Sedano, Carlos,Velasco, Rocío,Feberero, Claudia,Suárez-Pantiga, Samuel,Sanz, Roberto
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supporting information
p. 6365 - 6369
(2020/08/24)
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- Metal-Free Direct Deoxygenative Borylation of Aldehydes and Ketones
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Direct conversion of aldehydes and ketones into alkylboronic esters via deoxygenative borylation represents an unknown yet highly desirable transformation. Herein, we present a one-step and metal-free method for carbonyl deoxy-borylation under mild conditions. A wide range of aromatic aldehydes and ketones are tolerated and successfully converted into the corresponding benzylboronates. By the same deoxygenation manifold with aliphatic aldehydes and ketones, we also enable a concise synthesis of 1,1,2-tris(boronates), a family of compounds that currently lack efficient synthetic methods. Given its simplicity and versatility, we expect that this novel borylation approach could show great promise in organoboron synthesis and inspire more carbonyl deoxygenative transformations in both academic and industrial settings.
- Huang, Chia-Yu,Li, Chao-Jun,Li, Jianbin,Qiu, Zihang,Wang, Haining
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p. 13011 - 13020
(2020/09/01)
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- Nickel Catalyzed Intermolecular Carbonyl Addition of Aryl Halide
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In this study, we develop a nickel-catalyzed carbonyl arylation reaction employing aldehydes with aryl and allyl halides. Various aryl, α,β-unsaturated aldehyde and aliphatic aldehydes can be converted into their corresponding secondary alcohols in moderate-to-high yields. In addition, we extended this approach to develop an asymmetric reductive coupling reaction that combines nickel salts with chiral bisoxazoline ligands to give secondary alcohols with moderate enantioselectivity.
- Ishida, Seima,Suzuki, Hiroyuki,Uchida, Seiichiro,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 7483 - 7487
(2019/12/11)
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- Organic synthesis in a modular robotic system driven by a chemical programming language
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The synthesis of complex organic compounds is largely a manual process that is often incompletely documented. To address these shortcomings, we developed an abstraction that maps commonly reported methodological instructions into discrete steps amenable to automation. These unit operations were implemented in a modular robotic platform by using a chemical programming language that formalizes and controls the assembly of the molecules. We validated the concept by directing the automated system to synthesize three pharmaceutical compounds, diphenhydramine hydrochloride, rufinamide, and sildenafil, without any human intervention. Yields and purities of products and intermediates were comparable to or better than those achieved manually. The syntheses are captured as digital code that can be published, versioned, and transferred flexibly between platforms with no modification, thereby greatly enhancing reproducibility and reliable access to complex molecules.
- Steiner, Sebastian,Wolf, Jakob,Glatzel, Stefan,Andreou, Anna,Granda, Jaros?aw M.,Keenan, Graham,Hinkley, Trevor,Aragon-Camarasa, Gerardo,Kitson, Philip J.,Angelone, Davide,Cronin, Leroy
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