- 3-Acetoxyquinuclidine as Catalyst in Electron Donor-Acceptor Complex-Mediated Reactions Triggered by Visible Light
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3-Acetoxyquinuclidine was found to act as a catalytic electron donor species in a variety of electron donor-acceptor complex-mediated reactions. Only substoichiometric amounts (10-25 mol %) were needed to trigger the desired reaction. The outcome could be tuned by selecting the nature of the formed radical to perform amino- and hydro-decarboxylation, dimerization, and cyclization reactions. Importantly, no external additives were needed in this reaction.
- Bosque, Irene,Bach, Thorsten
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- Indium(III)-catalyzed reductive monoalkylation of electron-rich benzenes with aliphatic carboxylic acids leading to arylalkane derivatives
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Described herein is the reaction of electron-rich aromatic compounds with aliphatic carboxylic acids treated with a catalytic amount (5 mol-%) of InI3, 1,1,3,3-tetramethyldisiloxane (TMDS), and molecular iodine. The reductive monoalkylation occurs smoothly to produce the corresponding arylalkane derivatives.
- Moriya, Toshimitsu,Takayama, Kentaro,Konakahara, Takeo,Ogiwara, Yohei,Sakai, Norio
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- ELECTRON TRANSFER ON CIS- AND TRANS-1,2-DIPHENYLCYCLOPROPANE: STEREOISOMERIZATION AND FORMATION OF 1,3-DIPHENYLPROPENE AND 1,3-DIPHENYLPROPANE
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Reaction of cis- or trans-1,2-diphenylcyclopropane with Na/K leads to stereoisomerization and (after protonation) to 1,3-diphenylpropane and 1,3-diphenylpropene, the latter not being formed by H-migration.
- Boche, Gernot,Schneider, Dieter R.,Wernicke, Klaus
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- Acceleration of CuI-catalyzed coupling reaction of alkyl halides with aryl Grignard reagents using lithium chloride
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In the presence of LiCl, CuI-catalyzed coupling reaction of R(alkyl)-X with Ar(aryl)MgBr at rt was completed within 2 h. Effective leaving groups X in R-X were Br, I, OTs, but not Cl. Grignard reagents ArMgBr with both standard and bulky Ar such as 2-MeC
- Nakata, Kenya,Feng, Chao,Tojo, Toshifumi,Kobayashi, Yuichi
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- Hydrodefluorination and other hydrodehalogenation of aliphatic carbon-halogen bonds using silylium catalysis
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Trialkylsilylium cation equivalents partnered with halogenated carborane anions (such as Et3Si[HCB11H5Cl6]) function as efficient and long-lived catalysts for hydrodehalogenation of C-F, C-Cl, and C-Br bonds with trialkylsilanes as stoichiometric reagents. Only C(sp3)-halogen bonds undergo this reaction. The range of C-F bond-containing substrates that participate in this reaction is quite broad and includes simple alkyl fluorides, benzotrifluorides, and compounds with perfluoroalkyl groups attached to an aliphatic chain. However, CF4 has proven immune to this reaction. Hydrodechlorination was carried out with a series of alkyl chlorides and benzotrichlorides, and hydrodebromination was studied only with primary alkyl bromide substrates. Competitive experiments established a pronounced kinetic preference of the catalytic system for activation of a carbon-halogen bond of a lighter halide in primary alkyl halides. On the contrary, hydrodechlorination of C6F 5CCl3 proceeded much faster than hydrodefluorination of C6F5CF3 in one-pot experiments. A solid-state structure of Et3Si[HCB11H5Cl6] was determined by X-ray diffraction methods.
- Douvris, Christos,Nagaraja,Chen, Chun-Hsing,Foxman, Bruce M.,Ozerov, Oleg V.
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- Copper-catalyzed cross-coupling reactions of non-activated primary, secondary or tertiary alkyl chlorides with phenylmagnesium bromide
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Efficient copper-catalyzed cross-coupling reactions of non-activated alkyl chlorides, including primary, secondary, and tertiary alkyl chlorides, with phenyl Grignard reagents were achieved. Preparation of phenylmagnesium bromide in 2-methyltetrahydrofuran is critical for the success of the reaction. This protocol expands the synthetic toolbox for the construction of C[sbnd]C bonds of non-activated primary, secondary, and tertiary alkyl chlorides via copper-catalyzed cross-coupling.
- Tao, Chuanzhou,Sun, Lei,Wang, Bin,Liu, Zhou,Zhai, Yadong,Zhang, Xiulian,Shi, Dahua,Liu, Weiwei
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- A four-member ring hypervalent iodine radical
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A four-member ring hypervalent iodine radical has been detected in the laser flash photolysis of 1,3-diiodo-1,3-diphenylpropane. This species absorbs at 320 nm, has a lifetime of ～9.5 μs in cyclohexane, and is not quenchable by oxygen. Excitation of this radical by means of laser-drop photolysis results the formation of trans-1,2-diphenylcyclopropane through concerted iodine extrusion.
- Miranda, Miguel A.,Perez-Prieto, Julia,Font-Sanchis, Enrique,Konya, Klara,Scaiano
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- Reductive decarboxylation of N-(acyloxy)phthalimides via redox-initiated radical chain mechanism
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Highly efficient reductive decarboxylation of N-(acyloxy)phthalimides which are readily prepared from carboxylic acids was achieved by visible light irradiation using Ru(bpy)3Cl2 as a sensitizer in the presence of BNAH and t-BuSH via radical chain mechanism.
- Okada,Okubo,Morita,Oda
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- Lamp versus laser photolysis of 1,3-dichloro-1,3-diphenylpropane in cyclohexane. Direct observation of 1,3-diphenylpropenyl radical
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Laser photolysis of the title compound leads to two-photon processes indicating the involvement of the 1,3-diphenylpropanediyl biradical (12) and the 1,3-diphenylallyl radical (10).
- Perez-Prieto, Julia,Miranda, Miguel Angel,Font-Sanchis, Enrique,Konya, Klara,Scaiano
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- Iron pincer complexes as catalysts and intermediates in alkyl-aryl kumada coupling reactions
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Iron-catalyzed alkyl-aryl Kumada coupling has developed into an efficient synthetic method, yet its mechanism remains vague. Here, we apply a bis(oxazolinylphenyl)amido pincer ligand (Bopa) to stabilize the catalytically active Fe center, resulting in isolation and characterization of well-defined iron complexes whose catalytic roles have been probed and confirmed. Reactivity studies of the iron complexes identify an Fe(II) "ate" complex, [Fe(Bopa-Ph)(Ph)2]-, as the active species for the oxidative addition of alkyl halide. Experiments using radical-probe substrates and DFT computations reveal a bimetallic and radical mechanism for the oxidative addition. The kinetics of the coupling of an alkyl iodide with PhMgCl suggests that formation of the "ate" complex, rather than oxidative addition, is the turnover-determining step. This work provides insights into iron-catalyzed cross-coupling reactions of alkyl halides.
- Bauer, Gerald,Wodrich, Matthew D.,Scopelliti, Rosario,Hu, Xile
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- Direct and Unified Access to Carbon Radicals from Aliphatic Alcohols by Cost-Efficient Titanium-Mediated Homolytic C?OH Bond Cleavage
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Low-valent Ti-mediated homolytic C?O bond cleavage offers unified access to carbon radicals from ubiquitous non-activated tertiary, secondary, and even primary alcohols. In contrast to the representative Ti reagents, which were ineffective for this purpos
- Suga, Takuya,Takahashi, Yuuki,Miki, Chinatsu,Ukaji, Yutaka
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- Electrochemical Ring-Opening Dicarboxylation of Strained Carbon-Carbon Single Bonds with CO2: Facile Synthesis of Diacids and Derivatization into Polyesters
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Diacids are important monomers in the polymer industry to construct valuable materials. Dicarboxylation of unsaturated bonds, such as alkenes and alkynes, with CO2 has been demonstrated as a promising synthetic method. However, dicarboxylation of C-C single bonds with CO2 has rarely been investigated. Herein we report a novel electrochemical ring-opening dicarboxylation of C-C single bonds in strained rings with CO2. Structurally diverse glutaric acid and adipic acid derivatives were synthesized from substituted cyclopropanes and cyclobutanes in moderate to high yields. In contrast to oxidative ring openings, this is also the first realization of an electroreductive ring-opening reaction of strained rings, including commercialized ones. Control experiments suggested that radical anions and carbanions might be the key intermediates in this reaction. Moreover, this process features high step and atom economy, mild reaction conditions (1 atm, room temperature), good chemoselectivity and functional group tolerance, low electrolyte concentration, and easy derivatization of the products. Furthermore, we conducted polymerization of the corresponding diesters with diols to obtain a potential UV-shielding material with a self-healing function and a fluorine-containing polyester, whose performance tests showed promising applications.
- Liao, Li-Li,Wang, Zhe-Hao,Cao, Ke-Gong,Sun, Guo-Quan,Zhang, Wei,Ran, Chuan-Kun,Li, Yiwen,Chen, Li,Cao, Guang-Mei,Yu, Da-Gang
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supporting information
p. 2062 - 2068
(2022/02/10)
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- NHC-Iridium-Catalyzed Deoxygenative Coupling of Primary Alcohols Producing Alkanes Directly: Synergistic Hydrogenation with Sodium Formate Generated in Situ
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The direct conversion of alcohols into long-chain alkanes is an attractive but extremely challenging approach for biomass upgrading. Here, we describe the highly selective deoxygenative coupling of aryl ethanols with primary alcohols to produce alkanes, using a bis-N-heterocyclic carbene iridium (bis-NHC-Ir) complex as the catalyst. Up to quantitative yields and selectivity with a broad substrate scope are attained in both homo- and cross-coupling reactions. Mechanistic studies reveal that the further synergistic hydrogenation of the alkene intermediates by the formate generated in situ in the presence of bis-NHC-Ir is crucial for alkane production.
- Lu, Zeye,Zheng, Qingshu,Yang, Siqi,Qian, Chun,Shen, Yajing,Tu, Tao
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p. 10796 - 10801
(2021/09/08)
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- Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
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We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
- Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
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p. 13337 - 13347
(2021/11/20)
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- Method for preparing alkane through coupling of primary alcohol catalyzed by N-heterocyclic carbene metal compound
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The invention belongs to the technical field of transition metal catalysis and coupling reaction of biomass alcohol, and particularly relates to a method for preparing alkane in one step through self-coupling and cross-coupling of primary alcohol catalyzed by an N-heterocyclic carbene metal compound. The invention firstly provides a catalyst, namely a homogeneous N-heterocyclic carbene metal compound, for preparing alkane through primary alcohol coupling. The method comprises the following steps: by taking primary alcohol as a reaction raw material, tert-butyl alcohol salt of alkali metal, hydroxide and other strong alkalis as alkalis, the N-heterocyclic carbene metal compound as a catalyst and tertiary alcohol, benzene analogue or long-chain alkane as a solvent, reacting at 80-200 DEG C for 4-24 hours to obtain a corresponding alkane product. Compared with the prior art, the method disclosed by the invention has the advantages that the cheap and easily available biomass alcohol can be used as the starting raw material, the use of toxic phosphine-containing ligands with poor stability is avoided, the reaction selectivity and the yield can be quantified, the operation is simple and convenient, different high-purity alkane products can be obtained only through simple post-treatment, and the method is suitable for industrial amplification and application.
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Paragraph 0101-0106
(2021/08/19)
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- A Ball-Milling-Enabled Cross-Electrophile Coupling
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The nickel-catalyzed cross-electrophile coupling of aryl halides and alkyl halides enabled by ball-milling is herein described. Under a mechanochemical manifold, the reductive C-C bond formation was achieved in the absence of bulk solvent and air/moisture sensitive setups, in reaction times of 2 h. The mechanical action provided by ball milling permits the use of a range of zinc sources to turnover the nickel catalytic cycle, enabling the synthesis of 28 cross-electrophile coupled products.
- Jones, Andrew C.,Nicholson, William I.,Leitch, Jamie A.,Browne, Duncan L.
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supporting information
p. 6337 - 6341
(2021/08/23)
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- Chemoselective Hydrosilylation of the α,β-Site Double Bond in α,β- And α,β,γ,δ-Unsaturated Ketones Catalyzed by Macrosteric Borane Promoted by Hexafluoro-2-propanol
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The B(C6F5)3-catalyzed chemoselective hydrosilylation of α,β- and α,β,γ,δ-unsaturated ketones into the corresponding non-symmetric ketones in mild reaction conditions is developed. Nearly 55 substrates including those bearing reducible functional groups such as alkynyl, alkenyl, cyano, and aromatic heterocycles are chemoselectively hydrosilylated in good to excellent yields. Isotope-labeling studies revealed that hexafluoro-2-propanol also served as a hydrogen source in the process.
- Zhan, Xiao-Yu,Zhang, Hua,Dong, Yu,Yang, Jian,He, Shuai,Shi, Zhi-Chuan,Tang, Lei,Wang, Ji-Yu
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p. 6578 - 6592
(2020/07/17)
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- Method for hydrogenolysis of halides
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The invention discloses a method for hydrogenolysis of halides. The invention discloses a preparation method of a compound represented by a formula I. The preparation method comprises the following step: in a polar aprotic solvent, zinc, H2O and a compound represented by a formula II are subjected to a reaction as shown in the specification, wherein X is halogen; Y is -CHRR or R; hydrogenin H2O exists in the form of natural abundance or non-natural abundance. According to the preparation method, halide hydrogenolysis can be simply, conveniently and efficiently achieved through a simple and mild reaction system, and good functional group compatibility and substrate universality are achieved.
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- Hydrodecyanation of Secondary Alkyl Nitriles and Malononitriles to Alkanes using DiMeImd-BH3
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The decyanation of secondary aliphatic nitriles and the 2-fold decyanation of malononitriles leading to alkanes in the presence of 1,3-dimethylimidazol-2-ylidene borane (diMeImd-BH3) are reported. These reactions proceed via a radical mechanism that involves the addition of a borane radical to the nitrile to form an iminyl radical, followed by cleavage of a carbon-carbon bond. Theoretical calculations suggest that the β-cleavage of these iminyl radicals, which affords NHC-BH2CN and the corresponding alkyl radicals, is the rate-determining step in this reaction.
- Kawamoto, Takuji,Oritani, Kyohei,Kawabata, Atsushi,Morioka, Tsubasa,Matsubara, Hiroshi,Kamimura, Akio
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p. 6137 - 6142
(2020/05/22)
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- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
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The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
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p. 13841 - 13857
(2019/10/17)
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- Aldehydes as Alkylating Agents for Ketones
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Common and non-toxic aldehydes are proposed as reagents for alkylation of ketones instead of carcinogenic alkyl halides. The developed reductive alkylation reaction proceeds in the presence of the commercially available ruthenium catalyst [(cymene)RuCl2]2 (as low as 250 ppm) and carbon monoxide as the reducing agent. The reaction works well for a broad substrate scope, including aromatic and aliphatic aldehydes and ketones. It can be carried out without a solvent and often gives nearly quantitative yields of the products. This straightforward and cost-effective method is promising not only for laboratory application but also for industry, which produces carbon monoxide as a large-scale waste product.
- Runikhina, Sofiya A.,Afanasyev, Oleg I.,Biriukov, Klim,Perekalin, Dmitry S.,Klussmann, Martin,Chusov, Denis
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p. 16225 - 16229
(2019/11/22)
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- Metal-Reductant-Free Electrochemical Nickel-Catalyzed Couplings of Aryl and Alkyl Bromides in Acetonitrile
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While reductive cross-electrochemical coupling is an attractive approach for the synthesis of complex molecules at both small and large scale, two barriers for large-scale applications have remained: the use of stoichiometric metal reductants and a need for amide solvents. In this communication, new conditions that address these challenges are reported. The nickel-catalyzed reductive cross-coupling of aryl bromides with alkyl bromides can be conducted in a divided electrochemical cell using acetonitrile as the solvent and diisopropylamine as the sacrificial reductant to afford coupling products in synthetically useful yields (22-80%). Additionally, the use of a combination of the ligands 4,4′,4″-tri-tert-butyl-2,2′:6′,2′-terpyridine and 4,4′-di-tert-butyl-2,2′-bipyridine is essential to achieve high yields.
- Perkins, Robert J.,Hughes, Alexander J.,Weix, Daniel J.,Hansen, Eric C.
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supporting information
p. 1746 - 1751
(2019/08/20)
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- Ruthenium and Iron-Catalysed Decarboxylative N-alkylation of Cyclic Α-Amino Acids with Alcohols: Sustainable Routes to Pyrrolidine and Piperidine Derivatives
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A modular and waste-free strategy for constructing N-substituted cyclic amines via decarboxylative N-alkylation of α-amino acids employing ruthenium- and iron-based catalysts is presented. The reported method allows the synthesis of a wide range of five- and six-membered N-alkylated heterocycles in moderate-to-excellent yields starting from predominantly proline and a broad range of benzyl alcohols, and primary and secondary aliphatic alcohols. Examples using pipecolic acid for the construction of piperidine derivatives, as well as the one-pot synthesis of α-amino nitriles, are also shown.
- Afanasenko, Anastasiia,Hannah, Rachael,Yan, Tao,Elangovan, Saravanakumar,Barta, Katalin
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p. 3801 - 3807
(2019/07/31)
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- Dimeric Potassium Amide-Catalyzed α-Alkylation of Benzyl Sulfides and 1,3-Dithianes
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The first catalytic α-alkylation reaction of benzyl sulfides and 1,3-dithianes with styrenes and conjugated dienes was developed under mild conditions by using a readily available Br?nsted base potassium bis(trimethylsilyl)amide (KHMDS) as catalyst. The reaction displayed good functional group tolerance, high efficiency, and excellent chemoselectivity. A series of desired alkylation products were obtained in good to high yield. Preliminary mechanism studies suggested that two of the potassium amide catalyst molecules worked together in the catalytic cycle.
- Liu, Yu-Feng,Zheng, Lei,Zhai, Dan-Dan,Zhang, Xiang-Yu,Guan, Bing-Tao
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supporting information
p. 5351 - 5356
(2019/07/03)
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- Rhodium Porphyrin Catalyzed Regioselective Transfer Hydrogenolysis of C-C σ-Bonds in Cyclopropanes with iPrOH
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A new rhodium porphyrin catalyzed regioselective transfer hydrogenolysis of both activated and unactivated cyclopropanes employing iPrOH as the hydrogen source was discovered. The reaction mechanism for the C-C σ-bond activation of cyclopropanes was identified through an initial radical substitution with rhodium(II) metalloporphyrin radical to give a rhodium porphyrin alkyl, followed by hydrogenolysis with iPrOH to give the corresponding acyclic alkanes and regenerate rhodium(II) metalloporphyrin radical.
- Chen, Chen,Feng, Shiyu,Chan, Kin Shing
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p. 2582 - 2589
(2019/07/02)
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- Ni-Catalyzed Electrochemical Decarboxylative C-C Couplings in Batch and Continuous Flow
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An electrochemically driven, nickel-catalyzed reductive coupling of N-hydroxyphthalimide esters with aryl halides is reported. The reaction proceeds under mild conditions in a divided electrochemical cell and employs a tertiary amine as the reductant. This decarboxylative C(sp3)-C(sp2) bond-forming transformation exhibits excellent substrate generality and functional group compatibility. An operationally simple continuous-flow version of this transformation using a commercial electrochemical flow reactor represents a robust and scalable synthesis of value added coupling process.
- Li, Hui,Breen, Christopher P.,Seo, Hyowon,Jamison, Timothy F.,Fang, Yuan-Qing,Bio, Matthew M.
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supporting information
p. 1338 - 1341
(2018/03/09)
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- Sulfonic acid anchored on silica, SiO2@SO3H: A superior solid acid catalyst for quick and solvent-free reductive-deoxygenation of ketones with NaBH3CN
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NaBH3CN as a modified hydroborate agent and due to a strong withdrawing CN group does not show any reducing ability to reduce functional groups in the absence of acidic media (pH ~ 3–4). In this study, the immobilized sulfonic acid on silica, SiO2@SO3H, was prepared and applied as a new solid acid catalyst for extremely enhancing the reducing ability of NaBH3CN. The influence of SiO2@SO3H was highlighted by performing the quick and green reduction of structurally diverse carbonyl compounds involving aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones, and acyloins to the corresponding alcohols or alkanes with NaBH3CN. By the NaBH3CN/SiO2@SO3H system, aldehydes were reduced to the corresponding alcohols and ketonic compounds to alkanes as reductive-deoxygenation products. All reduction reactions were carried out within 3 min at room temperature and under solvent-free conditions to afford the products in high to excellent yields (90–98%).
- Zeynizadeh, Behzad,Kouhkan, Mehri
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p. 1521 - 1528
(2018/11/23)
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- Switchable Selectivity in the Pd-Catalyzed Alkylative Cross-Coupling of Esters
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The Pd-catalyzed cross-coupling of phenyl esters and alkyl boranes is disclosed. Two reaction modes are rendered accessible in a selective fashion by interchange of the catalyst. With a Pd-NHC system, alkyl ketones can be prepared in good yields via a Suzuki-Miyaura reaction proceeding by activation of the C(acyl)-O bond. Use of a Pd-dcype catalyst enables alkylated arenes to be synthesized by a modified pathway with extrusion of CO. Applications of this divergent coupling strategy and the origin of the switchable selectivity are discussed.
- Masson-Makdissi, Jeanne,Vandavasi, Jaya Kishore,Newman, Stephen G.
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p. 4094 - 4098
(2018/07/15)
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- Thiol-Catalyzed Radical Decyanation of Aliphatic Nitriles with Sodium Borohydride
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Radical decyanation of aliphatic nitriles was achieved in the presence of NaBH4 and a thiol. The reaction proceeds via a radical mechanism involving borane radical anion addition to nitrile to form an iminyl radical, which undergoes carbon-carbon cleavage. Reductive radical addition to acrylonitrile is followed by decyanation to give a two-carbon homologated product in a net radical ethylation reaction.
- Kawamoto, Takuji,Oritani, Kyohei,Curran, Dennis P.,Kamimura, Akio
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supporting information
p. 2084 - 2087
(2018/04/16)
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- Ligand-Controlled Nickel-Catalyzed Reductive Relay Cross-Coupling of Alkyl Bromides and Aryl Bromides
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1,1-Diarylalkanes are important structural frameworks which are widespread in biologically active molecules. Herein, we report a reductive relay cross-coupling of alkyl bromides with aryl bromides by nickel catalysis with a simple nitrogen-containing ligand. This method selectively affords 1,1-diarylalkane derivatives with good to excellent yields and regioselectivity.
- Peng, Long,Li, Yuqiang,Li, Yangyang,Wang, Wang,Pang, Hailiang,Yin, Guoyin
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p. 310 - 313
(2018/01/17)
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- Photochemical Nickel-Catalyzed Reductive Migratory Cross-Coupling of Alkyl Bromides with Aryl Bromides
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A novel method to access 1,1-diarylalkanes from readily available, nonactivated alkyl bromides and aryl bromides via visible-light-driven nickel and iridium dual catalysis, wherein diisopropylamine (iPr2NH) is used as the terminal stoichiometric reductant, is reported. Both primary and secondary alkyl bromides can be successfully transformed into the migratory benzylic arylation products with good selectivity. Additionally, this method showcases tolerance toward a wide array of functional groups and the presence of bases.
- Peng, Long,Li, Zheqi,Yin, Guoyin
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supporting information
p. 1880 - 1883
(2018/04/16)
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- Ru-Catalyzed Completely Deoxygenative Coupling of 2-Arylethanols through Base-Induced Net Decarbonylation
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Substituted arylethanols can be coupled by using a readily available Ru catalyst in a fully deoxygenative manner to produce hydrocarbon chains in one step. Control experiments indicate that the first deoxygenation occurs through an aldol condensation, whereas the second occurs through a base-induced net decarbonylation. This double deoxygenation enables further development in the use of alcohols as versatile and green alkylating reagents, as well as in other fields, such as deoxygenation and upgrading of overfunctionalized biomass to produce hydrocarbons.
- Manojveer, Seetharaman,Forrest, Sebastian J. K.,Johnson, Magnus T.
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supporting information
p. 803 - 807
(2018/01/27)
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- Iron-Catalyzed Remote Arylation of Aliphatic C-H Bond via 1,5-Hydrogen Shift
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Catalytic amounts of an iron(III) salt and a N-heterocyclic carbene ligand catalyze the arylation of 2-iodoalkylarenes with diphenylzinc selectively at the C-H bond of the alkyl side chain. Several lines of evidence suggest that the iron catalyst reacts with the aryl iodide moiety of the substrate to generate an aryliron intermediate that behaves in a radical manner and cleaves the aliphatic C-H bond through 1,5-hydrogen transfer; the resulting alkyliron intermediate undergoes reductive elimination to give the arylated product.
- Zhou, Bingwei,Sato, Hiroki,Ilies, Laurean,Nakamura, Eiichi
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- Pd/C-Al-water facilitated selective reduction of a broad variety of functional groups
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The chemoselective reduction of a broad variety of functional groups by a Pd/C-Al-H2O system is described. The reduction is based on the reaction of Al with the solvent water that in situ produces hydrogen that is utilized by the supported Pd catalyst toward the hydrogenation of the target functional groups. The hydrogenations are carried out under mild conditions and provided the products in high yields and selectivity. The reduction system appeared to be effective for a broad range of functional groups, including C-C, C-N, C-O and N-O multiple bonds, aromatic rings, hydrogenolysis of C-O, C-N and C-Halogen bonds. The appropriate selection of the reaction conditions allowed the selective preparation of different products from the same substrate. The simplicity, cost, tunability and the environmentally benign character of the catalytic system offer numerous advantages over the currently available methods.
- Sch?fer,Ellstrom,Cho,T?r?k
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p. 1230 - 1234
(2017/03/20)
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- A novel route to the synthesis of α,Ω-diphenylalkanes
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A novel route to the synthesis of α,ω-diphenylalkanes is reported. Toluene was metalated in the benzylic position by n-butyllithium with THF as an activating reagent, and then directly reacted with α,ω-dichloroalkanes to obtain the target product. This process provides a facile and efficient route to the synthesis of α,Ω-diphenylalkanes.
- Chen, Hui,Chen, Yancai,Zhang, Yinlong,Yang, Zhenqiang,Li, Ji,Yang, Ruina,Wang, Wenxin
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p. 473 - 474
(2017/08/18)
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- Efficient phosphine-mediated formal C(sp3)-C(sp3) coupling reactions of alkyl halides in batch and flow
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The construction of C(sp3)-C(sp3) bond is an essential chemical transformation in synthetic chemistry due to its abundance in organic scaffolds. Here we demonstrate a valuable adaptation of the Wittig-type chemical procedure to efficiently facilitate C(sp3)-C(sp3) bond formation utilizing a range of alkyl building blocks. Additionally the method is amenable with flow synthesis to afford coupled products in good to excellent yields without laborious purification process.
- Tran,Hock,Gordon,Koenigs,Nguyen
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supporting information
p. 4950 - 4953
(2017/07/11)
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- Effects of substituents on NMR chemical shifts and mass fragmentation patterns of 1-aryl-3-phenylpropanes
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The 1H and 13C chemical shifts and the mass spectral fragmentation patterns of 1-aryl-3-phenylpropanes with m- or p-substituents (H, NO2, Br, Cl, OCH3, CH3) were studied. The electronic effects of the substi-tuents seemed to be transmitted by the through-space as well as by a through-bond mechanism, resulting in an inverse correlation in the plot of the chemical shift values of i-C vs. the Hammett σ values. The mass spectra showed the substituted benzyl fragments as the base peaks when the substituents were electron donating, whereas the benzyl fragment was observed as the base peaks with the electron-withdrawing substituents.
- Jeong, Eun Jeong,Lee, In-Sook Han
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p. 538 - 543
(2016/04/26)
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- Decarboxylative Cross-Electrophile Coupling of N-Hydroxyphthalimide Esters with Aryl Iodides
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A new method for the decarboxylative coupling of alkyl N-hydroxyphthalimide esters (NHP esters) with aryl iodides is presented. In contrast to previous studies that form alkyl radicals from carboxylic acid derivatives, no photocatalyst, light, or arylmetal reagent is needed, only nickel and a reducing agent (Zn). Methyl, primary, and secondary alkyl groups can all be coupled in good yield (77% ave yield). One coupling with an acid chloride is also presented. Stoichiometric reactions of (dtbbpy)Ni(2-tolyl)I with an NHP ester show for the first time that arylnickel(II) complexes can directly react with NHP esters to form alkylated arenes.
- Huihui, Kierra M. M.,Caputo, Jill A.,Melchor, Zulema,Olivares, Astrid M.,Spiewak, Amanda M.,Johnson, Keywan A.,Dibenedetto, Tarah A.,Kim, Seoyoung,Ackerman, Laura K. G.,Weix, Daniel J.
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p. 5016 - 5019
(2016/05/19)
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- Copper-Catalyzed Boron-Selective C(sp2)-C(sp3) Oxidative Cross-Coupling of Arylboronic Acids and Alkyltrifluoroborates Involving a Single-Electron Transmetalation Process
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A rapid and highly selective oxidative cross-coupling reaction between readily available and shelf-stable arylboronic acids and primary or secondary potassium alkyltrifluoroborates was devised and developed, which works under mild conditions using copper(II) acetate as the catalyst and silver oxide as the oxidant. Initial experimental results indicate that a single-electron transmetalation process is involved. This approach effectively bypasses the problems associated with the traditional cross-coupling reactions of alkylboronates and thus provides a complementary method in building C(sp2)-C(sp3) bonds.
- Ding, Siyi,Xu, Liang,Li, Pengfei
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p. 1329 - 1333
(2016/02/18)
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- A Concise and Atom-Economical Suzuki-Miyaura Coupling Reaction Using Unactivated Trialkyl- and Triarylboranes with Aryl Halides
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A concise and atom-economical Suzuki-Miyaura coupling of trialkyl- and triarylboranes with aryl halides is described. This new protocol represents the first general, practical method that efficiently utilizes peralkyl and peraryl groups of the unactivated trialkyl- and triarylboranes for the Suzuki-Miyaura coupling reaction.
- Li, Hongmei,Zhong, Yong-Li,Chen, Cheng-Yi,Ferraro, Ashley E.,Wang, Dengjin
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supporting information
p. 3616 - 3619
(2015/07/28)
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- Iron-catalyzed olefin hydrogenation at 1 bar H2 with a FeCl3-LiAlH4 catalyst
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The scope and mechanism of a practical protocol for the iron-catalyzed hydrogenation of alkenes and alkynes at 1 bar H2 pressure were studied. The catalyst is formed from cheap chemicals (5 mol% FeCl3-LiAlH4, THF). A homogeneous mechanism operates at early stages of the reaction while active nanoparticles form upon ageing of the catalyst solution. This journal is
- Gieshoff, Tim N.,Villa, Matteo,Welther, Alice,Plois, Markus,Chakraborty, Uttam,Wolf, Robert,Jacobi Von Wangelin, Axel
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supporting information
p. 1408 - 1413
(2015/03/18)
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- Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes
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An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.
- Qureshi, Ziyauddin S.,Sarawade, Pradip B.,Albert, Matthias,D'Elia, Valerio,Hedhili, Mohamed N.,K?hler, Klaus,Basset, Jean-Marie
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p. 635 - 642
(2015/03/05)
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- Hydrothermal photochemistry as a mechanistic tool in organic geochemistry: The chemistry of dibenzyl ketone
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Hydrothermal organic transformations under geochemically relevant conditions can result in complex product mixtures that form via multiple reaction pathways. The hydrothermal decomposition reactions of the model ketone dibenzyl ketone form a mixture of reduction, dehydration, fragmentation, and coupling products that suggest simultaneous and competitive radical and ionic reaction pathways. Here we show how Norrish Type I photocleavage of dibenzyl ketone can be used to independently generate the benzyl radicals previously proposed as the primary intermediates for the pure hydrothermal reaction. Under hydrothermal conditions, the benzyl radicals undergo hydrogen atom abstraction from dibenzyl ketone and para-coupling reactions that are not observed under ambient conditions. The photochemical method allows the primary radical coupling products to be identified, and because these products are generated rapidly, the method also allows the kinetics of the subsequent dehydration and Paal-Knorr cyclization reactions to be measured. In this way, the radical and ionic thermal and hydrothermal reaction pathways can be studied separately.
- Yang, Ziming,Lorance, Edward D.,Bockisch, Christiana,Williams, Lynda B.,Hartnett, Hilairy E.,Shock, Everett L.,Gould, Ian R.
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p. 7861 - 7871
(2015/03/18)
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- Palladium on graphene: The in situ generation of a catalyst for the chemoselective reduction of α,β-unsaturated carbonyl compounds
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Palladium-supported graphene oxide has been successfully applied as a catalyst precursor for the selective reduction of α,β-unsaturated carbonyl compounds. Pd nanoparticles were formed during the course of the reduction with only negligible leaching of the Pd species into the reaction mixture.
- Morimoto, Naoki,Yamamoto, Shun-Ichi,Takeuchi, Yasuo,Nishina, Yuta
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p. 15608 - 15612
(2013/09/12)
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- Room temperature synthesis of ZnAlPO4 nanoparticles and their catalytic applications
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Here, we report a simple method for the synthesis of ZnAlPO4 nanoparticles possessing stable structures even after the removal of the structure directing agent. The material can act as an efficient bi-functional catalyst for the alkylation of acetophenone with benzyl alcohol.
- Sreenivasulu, Peta,Nandan, Devaki,Sreedhar,Viswanadham, Nagabhatla
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p. 13651 - 13654
(2013/08/23)
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- Efficient palladium-catalyzed C-O hydrogenolysis of benzylic alcohols and aromatic ketones with polymethylhydrosiloxane
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A simple method has been developed for the reductive deoxygenation of aromatic ketones and benzylic alcohols in the presence of polymethylhydrosiloxane (PMHS). The reductive deoxygenation of aromatic ketones and benzylic alcohols, including secondary alcohols, to the corresponding methylene hydrocarbons has been achieved in good to excellent yields using palladium chloride (PdCl2) as catalyst and PMHS as hydride source. Such deoxygenations were successfully with aryl alkyl ketones and diaryl ketones, as exemplified by the reductive deoxygenation of acetophenone and benzopheneone, respectively. The corresponding benzylic alcohols and secondary alcohol analogues could also be converted into their respective methylene hydrocarbons by the PdCl2/PMHS system.
- Wang, Hu,Li, Li,Bai, Xing-Feng,Shang, Jun-Yan,Yang, Ke-Fang,Xu, Li-Wen
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supporting information
p. 341 - 347
(2013/05/08)
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- Pd-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols by formic acid: A mechanistic study
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A palladium-catalyzed transfer hydrogenolysis of primary, secondary, and tertiary benzylic alcohols by formic acid has been developed and studied. The product hydrocarbons were obtained in excellent yields from both secondary and tertiary benzylic alcohols and in good yields for primary benzylic alcohols. The rate of disappearance of 1-phenylethanol (1) follows zero-order dependence in 1 and first-order dependence in formic acid and palladium. Catalytic amounts of base inhibit a competing disproportionation reaction of alcohol to alkane and ketone, and an optimum was obtained when 5 equiv of base to palladium was used. Deuterium kinetic isotope studies for the transfer hydrogenolysis reveal individual isotope effects for the hydridic position (kCHOH/k CDOH = 2.26 ± 0.24) and the protic position (k CHOH/kCHOD = 0.62 ± 0.06) of the formic acid. Simultaneous deuteration in both positions of formic acid gave a combined isotope effect of (kCHOH/kCDOD = 1.41 ± 0.11). We propose a mechanism involving the following steps: a competitive inhibition of the open palladium site by adsorption of the formate anion to generate formato-palladium species, followed by a reversible protonation and a rate-limiting hydride transfer to obtain the active palladium with chemisorbed hydrogen that performs the hydrogenolysis of the alcohol in a fast reaction step.
- Sawadjoon, Supaporn,Lundstedt, Anna,Samec, Joseph S.M.
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p. 635 - 642
(2013/05/22)
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- Adducts, adducts and oligomers, or adducts, oligomers and low molecular weight polymers, and their preparation
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This invention provides adducts, mixtures of adducts and oligomers, and/or mixtures of adducts, oligomers, and low molecular weight polymers formed from monovinylaromatic hydrocarbons.
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Page/Page column 37
(2013/04/24)
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- Malononitrile-assisted highly chemoselective bismuth triflate catalyzed conjugate reduction of α,β-unsaturated ketones
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A very simple, direct, bismuth-catalyzed conjugate reduction protocol that allows for the catalytic regioselective formation of substituted ketones from enones under mild conditions has been developed. We have shown for the first time that the combined poly(methylhydro)siloxane-malononitrile system can serve as an efficient reductant/reagent in 1,4-conjugate reduction of enones. The regioselectivity, efficiencies, and experimental simplicity of the present method complements the more complex methods previously employed in copper or palladium-catalyzed reduction. This method should prove attractive because of its mild reaction conditions and the interesting chemistry of combining the use of poly(methylhydro)siloxane and malononitrile for selective reduction. Copyright
- Shang, Jun-Yan,Li, Fei,Bai, Xing-Feng,Jiang, Jian-Xiong,Yang, Ke-Fang,Lai, Guo-Qiao,Xu, Li-Wen
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supporting information; experimental part
p. 2809 - 2815
(2012/06/18)
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- Arylalkyl ketones, benzophenones, desoxybenzoins and chalcones inhibit TNF-α induced expression of ICAM-1: Structure-activity analysis
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The interaction between leukocytes and the vascular endothelial cells (EC) via cellular adhesion molecules plays an important role in the pathogenesis of various inflammatory and autoimmune diseases. Small molecules that block these interactions have been targeted as potential therapeutic agents against acute and chronic inflammatory diseases. In an effort to identify potent intercellular cell adhesion molecule-1 (ICAM-1) inhibitors, a large number of arylalkyl ketones, benzophenones, desoxybenzoins and chalcones and their analogs (54 in total) have been synthesized and screened for their ICAM-1 inhibitory activity. The structure-activity relationship studies of these compounds identified three potent chalcone derivatives and also demonstrated the possible mechanism for their ICAM-1 inhibitory activities. The most active compound was found to be 79. A large number of arylalkyl ketones, benzophenones, desoxybenzoins and chalcones as well as their analogs (54 in total) were synthesized and screened for their ICAM-1 inhibitory activity. The structure-activity relationship studies of these compounds identified three potent chalcone derivatives and also demonstrated a possible mechanism of their ICAM-1 inhibitory activities. The most active compound was found to be 79. Copyright
- Kumar, Sarvesh,Reddy L, Chandra Shekhar,Kumar, Yogesh,Kumar, Amit,Singh, Brajendra K.,Kumar, Vineet,Malhotra, Shashwat,Pandey, Mukesh K.,Jain, Rajni,Thimmulappa, Rajesh,Sharma, Sunil K.,Prasad, Ashok K.,Biswal, Shyam,Van Der Eycken, Erik,Depass, Anthony L.,Malhotra, Sanjay V.,Ghosh, Balaram,Parmar, Virinder S.
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p. 368 - 377
(2012/07/31)
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- A novel iron complex for cross-coupling reactions of multiple C-Cl bonds in polychlorinated solvents with grignard reagents
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A novel iron(III) complex (2) of a pincer ligand [1, N2,N6-bis(2,6- diisopropylphenyl)pyridine-2,6-dicarboxamide] was developed and used for remediation of polychlorinated solvents via sp3-sp3 coupling of Grignard reagents with C-Cl bonds. The use of an iron catalyst for such coupling reactions is highly desirable due to its greener and more economical nature. Complex 2 was characterized using various spectroscopic techniques: electrospray ionization mass spectrometer (ESI-MS, m/z 575.1), cyclic voltammetry (E 1/2, 0.03 V and ΔE, 0.97 V), and ultraviolet visible (UV/Vis) spectroscopic techniques. The iron(III) complex showed efficient activation of multiple C-Cl bonds and catalyzing C-C coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents under ambient reaction conditions. Complex 2 showed exceptional activity with reactions approaching near completion in about 5 min. With the required catalyst loading as low as 0.2 mol%, considerably high turnover numbers (TON = 483) and turnover frequency (TOF = 5,800 h-1) were obtained. None of the products detected during the reaction contained any chlorine, indicating an efficient dechlorination method while synthesizing products of synthetic and commercial interest. Interestingly, the catalyst was capable of replacing all chlorine atoms in each polychlorinated solvent under the investigations with high conversion. Springer Science+Business Media, LLC 2012.
- Gartia, Yashraj,Pulla, Sharon,Ramidi, Punnamchandar,Farris, Carolina Costa,Nima, Zeid,Jones, Darin E.,Biris, Alexandru S.,Ghosh, Anindya
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p. 1397 - 1404
(2013/01/15)
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- Cross coupling reactions of multiple CCl bonds of polychlorinated solvents with Grignard reagent using a pincer nickel complex
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The nickel(II) complex of a bulky pincer-type ligand, N,N′-bis(2,6- diisopropylphenyl)-2,6-pyridinedicarboxamido, was examined for sp 3-sp3 coupling of Grignard reagents with polychlorinated solvents. The nickel(II) complex catalyzed CC coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents. The effective activation of multiple CCl bonds proceeded under ambient reaction conditions and within a short time (20 min). This catalyst displays the highest activity yet reported for this reaction type, with catalyst loading as low as 0.4 mol% and turnover frequency (TOF) as high as 724 h-1. The catalyst is capable of replacing all chlorine atoms with CC bond formations for all of the polychlorinated solvents under investigation. The catalytic process could prove to be an efficient method of remediation of toxic polychlorinated solvents while generating synthetically and commercially important chemicals.
- Gartia, Yashraj,Nasini, Udaya Bhasker,Ghosh, Anindya,Biswas, Abhijit,Stadler, Matthew
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p. 322 - 327,6
(2020/07/30)
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- Electron transfer to benzenes by photoactivated neutral organic electron donor molecules
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Powerful reduction reactions: Simple organic electron donors, composed solely of the elements carbon, hydrogen, and nitrogen, reduce ground-state benzene rings to their radical anions by electron transfer upon photoactivation (DMF=dimethylformamide).
- Cahard, Elise,Schoenebeck, Franziska,Garnier, Jean,Cutulic, Sylvain P. Y.,Zhou, Shengze,Murphy, John A.
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p. 3673 - 3676
(2012/06/01)
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- Iridium-catalyzed reactions of ω-Arylalkanols to α,ω- Diarylalkanes
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The long and the short of it: An atom-economical route to α,ω-diarylalkanes from ω-arylalkanols was achieved by a direct one-step method, or a sequential two-step method depending on the alkyl chain length. The reaction proceeded through the formation of β-methylhydroxy- α,ω-diarylalkanes by dehydrogenation/β-alkylation, followed by dehydrogenation/decarbonylation. Copyright
- Obora, Yasushi,Anno, Yuka,Okamoto, Ryuhei,Matsu-Ura, Toyomi,Ishii, Yasutaka
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supporting information; experimental part
p. 8618 - 8622
(2011/11/11)
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