- Chemoselective and ligand-free aerobic oxidation of benzylic alcohols to carbonyl compounds using alumina-supported mesoporous nickel nanoparticle as an efficient recyclable heterogeneous catalyst
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An economically efficient and operationally simple ligand-free protocol for the chemoselective oxidation of benzylic alcohols to carbonyl compounds has been developed using alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst along with potassium tert-butoxide in the presence of aerial oxygen as an eco-friendly oxidant. The aliphatic alcohols remained unaffected under the present condition. Excellent chemoselectivity has also been demonstrated through intermolecular and intramolecular competition experiments. This protocol accommodates a diverse range of substituents with the tolerance of various sensitive moieties during the reaction. The catalyst could be recovered by filtration and reused consecutively without any significant loss in the catalytic activity. Moreover, the heterogeneity of the catalyst has also been established by the “hot filtration method (Sheldon's test)”.
- Das, Asit Kumar,Nandy, Sneha,Bhar, Sanjay
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- Enantioselective Synthesis of Bicyclopentane-Containing Alcohols via Asymmetric Transfer Hydrogenation
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Compounds a containing bicyclo[1.1.1]pentane (BCP) adjacent to a chiral center can be prepared with high enantiomeric excess through asymmetric transfer hydrogenation (ATH) of adjacent ketones. In the reduction step, the BCP occupies the position distant from the η6-arene of the catalyst. The reduction was applied to the synthesis of a BCP analogue of the antihistamine drug neobenodine.
- Vyas, Vijyesh K.,Clarkson, Guy J.,Wills, Martin
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supporting information
p. 3179 - 3183
(2021/05/04)
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- Suzuki coupling of aroyl-MIDA boronate esters – A preliminary report on scope and limitations
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Recent methodological reports for synthesizing acyl-MIDA boronate esters compel an investigation of their potential use as substrates in a standard Suzuki-Miyaura cross-coupling reaction. Here we report the production of benzophenones by C[sbnd]C cross coupling between a benzoyl-MIDA boronate ester and a multitude of aryl bromide substrates in adequate yields following optimization under ambient conditions outside of a glove box. Under these standard conditions, none of several acyl-MIDA boronate esters (in an alkyl series) serves as a competent coupling partner. The substrate scope is also limited by the finding that the corresponding trifluoroborates of both acyl- and aroyltrifluroborates are not suitable substrates. For reasons of availability and synthetic difficulty in procuring other aroyl-MIDA boronates, this preliminary study examines the reactivity of benzoyl-MIDA boronate with several aryl bromide substrates.
- Lai, Samson,Lin, Wen Xuan,Perrin, David M.,Takaesu, Noah
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- Tetramethylammonium Fluoride Alcohol Adducts for SNAr Fluorination
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Nucleophilic aromatic fluorination (SNAr) is among the most common methods for the formation of C(sp2)-F bonds. Despite many recent advances, a long-standing limitation of these transformations is the requirement for rigorously dry, aprotic conditions to maintain the nucleophilicity of fluoride and suppress the generation of side products. This report addresses this challenge by leveraging tetramethylammonium fluoride alcohol adducts (Me4NF·ROH) as fluoride sources for SNAr fluorination. Through systematic tuning of the alcohol substituent (R), tetramethylammonium fluoride tert-amyl alcohol (Me4NF·t-AmylOH) was identified as an inexpensive, practical, and bench-stable reagent for SNAr fluorination under mild and convenient conditions (80 °C in DMSO, without the requirement for drying of reagents or solvent). A substrate scope of more than 50 (hetero) aryl halides and nitroarene electrophiles is demonstrated.
- Bland, Douglas C.,Lee, So Jeong,Morales-Colón, Mariá T.,Sanford, Melanie S.,Scott, Peter J. H.,See, Yi Yang
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supporting information
p. 4493 - 4498
(2021/06/28)
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- AIBN initiated functionalization of the benzylic sp3 C[sbnd]H and C[sbnd]C bonds in the presence of dioxygen
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A sp3 C[sbnd]H bond functionalization and C[sbnd]C bond cleavage were realized by AIBN/O2 catalyst system, providing a series of benzophenones under mild reaction conditions. The mechanistic study shows that a peroxide intermediate is involved in this transformation, and in the case of diphenylmethanes, the sp3 C[sbnd]C bond is cleaved through the peroxide rearrangement, which might provides a new way to cleave relatively strong C[sbnd]C bond and be applied to more general C[sbnd]C bond activation.
- Hu, Yingying,Shao, Yu,Zhang, Shuwei,Yuan, Yuan,Sun, Zheng,Yuan, Yu,Jia, Xiaodong
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supporting information
(2021/02/01)
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- Suzuki-Miyaura cross-coupling of esters by selective O-C(O) cleavage mediated by air- And moisture-stable [Pd(NHC)(μ-Cl)Cl]2precatalysts: Catalyst evaluation and mechanism
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The cross-coupling of aryl esters has emerged as a powerful platform for the functionalization of otherwise inert acyl C-O bonds in chemical synthesis and catalysis. Herein, we report a combined experimental and computational study on the acyl Suzuki-Miyaura cross-coupling of aryl esters mediated by well-defined, air- and moisture-stable Pd(ii)-NHC precatalysts [Pd(NHC)(μ-Cl)Cl]2. We present a comprehensive evaluation of [Pd(NHC)(μ-Cl)Cl]2 precatalysts and compare them with the present state-of-the-art [(Pd(NHC)allyl] precatalysts bearing allyl-type throw-away ligands. Most importantly, the study reveals [Pd(NHC)(μ-Cl)Cl]2 as the most reactive precatalysts discovered to date in this reactivity manifold. The unique synthetic utility of this unconventional O-C(O) cross-coupling is highlighted in the late-stage functionalization of pharmaceuticals and sequential chemoselective cross-coupling, providing access to valuable ketone products by a catalytic mechanism involving Pd insertion into the aryl ester bond. Furthermore, we present a comprehensive study of the catalytic cycle by DFT methods. Considering the clear advantages of [Pd(NHC)(μ-Cl)Cl]2 precatalysts on several levels, including facile one-pot synthesis, superior atom-economic profile to all other Pd(ii)-NHC catalysts, and versatile reactivity, these should be considered as the 'first-choice' catalysts for all routine applications in ester O-C(O) bond activation.
- Cavallo, Luigi,Nolan, Steven P.,Poater, Albert,Szostak, Michal,Yang, Shiyi,Zhou, Tongliang
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p. 3189 - 3197
(2021/05/25)
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- A Simple Synthetic Route to Well-Defined [Pd(NHC)Cl(1-tBu-indenyl)] Pre-catalysts for Cross-Coupling Reactions
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The development of robust, more efficient, general, easily accessible Pd(II)–NHC pre-catalysts remains a key issue in cross-coupling applications. A selection of well-defined, air and moisture stable [Pd(NHC)Cl(1-tBu-indenyl)] (NHC=IPr, IPrCl, IMes, SIMes, IPr*) pre-catalysts have been synthesized in good to excellent yields by reacting [Pd(1-tBu-indenyl)(μ-Cl)]2 and various NHC?HCl precursors in the presence of the weak base K2CO3 in green acetone. The synthesized Pd(II)-NHC derivatives displayed excellent catalytic activity in classical Suzuki-Miyaura and Buchwald–Hartwig reactions, especially when IPrCl is employed as ancillary ligand. Additionally, in the challenging Suzuki-Miyaura reaction between esters and arylboronic acids, the [Pd(IPr*)Cl(1-tBu-indenyl)] complex exhibited the optimum catalytic activity under very mild reaction conditions.
- Beli?, Marek,Cazin, Catherine S. J.,Gobbo, Alberto,Liu, Yaxu,Nolan, Steven P.,Scattolin, Thomas,Van Hecke, Kristof
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- Novelmeta-benzothiazole and benzimidazole functionalised POCOP-Ni(ii) pincer complexes as efficient catalysts in the production of diarylketones
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The synthesis of four novel non-symmetric Ni(ii)-POCOP pincer complexesmeta-functionalized with either benzothiazole or benzimidazole at the central aryl ring is described. All complexes were fully characterised in solution by various analytical techniques and the molecular structures in the solid state of complexes1b,2aand2bwere unequivocally determined by single crystal X-ray diffraction analysis. In addition, the Ni(ii)-POCOP pincer complexes were efficiently used as catalysts in the synthesis of diarylketones by cross-coupling reactions of functionalized benzaldehydes and boronic acid derivatives under relatively mild conditions. An important aspect of this transformation is the dependence on the steric properties of the donor groups (OPR2) of the pincer ligands, the more active compounds having the phosphinitos bearing isopropyl groups (1aand2a) than those containingtert-butyl substituents (1band2b).
- Castillo-García, Antonio A.,González-Sebastián, Lucero,Lomas-Romero, Leticia,Hernandez-Ortega, Simon,Toscano, Ruben A.,Morales-Morales, David
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p. 10204 - 10216
(2021/06/18)
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- Self-Assembled 2,3-Dicyanopyrazino Phenanthrene Aggregates as a Visible-Light Photocatalyst
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In this study, 2,3-dicyanopyrazino phenanthrene (DCPP), a commodity chemical that can be prepared at an industrial scale, was used as a photocatalyst in lieu of Ru or Ir complexes in C-X (X = C, N, and O) bond-forming reactions under visible-light irradiation. In these reactions, [DCPP]n aggregates were formed in situ through physical π-πstacking of DCPP monomers in organic solvents. These aggregates exhibited excellent photo- and electrochemical properties, including a visible light response (430 nm), long excited-state lifetime (19.3 μs), high excited-state reduction potential (Ered([DCPP]n*/[DCPP]n·-) = +2.10 V vs SCE), and good reduction stability. The applications of [DCPP]n aggregates as a versatile visible-light photocatalyst were demonstrated in decarboxylative C-C cross-coupling, amidation, and esterification reactions.
- He, Min,Yu, Xiaoqiang,Wang, Yi,Li, Fei,Bao, Ming
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p. 5016 - 5025
(2021/04/12)
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- Gold complexes of bis-indazole-derived N-Heterocyclic carbene: Synthesis, structural characterizations, and catalysis
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A novel series of bis Indy-NHC gold complexes have been developed and investigated via a mild Ag-carbene transfer route. The obtained complexes were characterized by NMR spectroscopy and X-ray diffraction analysis. The catalytic property of these gold complexes was further evaluated in the oxidation of benzylic. The gold complex E1 showed a high catalytic activity in the oxidation of various benzylic substrates, resulting in the corresponding carbonyl compounds with excellent yields using TBHP as oxidant.
- Zhang, Hua,Xu, Ting,Li, Dongdong,Cheng, Tao,Chen, Jing,Zhou, Yang
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- Pd-Catalysed carbonylative Suzuki-Miyaura cross-couplings using Fe(CO)5under mild conditions: generation of a highly active, recyclable and scalable ‘Pd-Fe’ nanocatalyst
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The dual function and role of iron(0) pentacarbonyl [Fe(CO)5] has been identified in gaseous CO-free carbonylative Suzuki-Miyaura cross-couplings, in which Fe(CO)5supplied COin situ, leading to the propagation of catalytically active Pd-Fe nanoparticles. Compared with typical carbonylative reaction conditions, CO gas (at high pressures), specialised exogenous ligands and inert reaction conditions were avoided. Our developed reaction conditions are mild, do not require specialised CO high pressure equipment, and exhibit wide functional group tolerance, giving a library of biaryl ketones in good yields.
- Zhu, Zhuangli,Wang, Zhenhua,Jian, Yajun,Sun, Huaming,Zhang, Guofang,Lynam, Jason M.,McElroy, C. Robert,Burden, Thomas J.,Inight, Rebecca L.,Fairlamb, Ian J. S.,Zhang, Weiqiang,Gao, Ziwei
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supporting information
p. 920 - 926
(2021/02/09)
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- Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
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A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
- Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
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p. 13848 - 13852
(2021/04/22)
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- Method for preparing aldehyde ketone compound through olefin oxidation
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The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
- -
-
Paragraph 0019
(2021/04/07)
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- Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanoneviaCeCl3catalysis
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A Ce-catalyzed strategy is developed to produce biaryl methanonesviaphotooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
- Xie, Pan,Xue, Cheng,Du, Dongdong,Shi, SanShan
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supporting information
p. 6781 - 6785
(2021/08/20)
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- Photo-induced oxidative cleavage of C-C double bonds of olefins in water
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The carbonyl compounds, synthesized by the oxidative cleavage of their corresponding olefins, are of great significance in organic synthesis, especially aryl ketones. We have developed a gentle and effective protocol, using acid red 94 as the organic metal-free photocatalyst, O2 as the oxidant, and water as the solvent. Under visible light irradiation, aryl ketone derivatives were obtained in moderate to excellent yields, showing good economic and environmental advantages.
- Zhang, Yilan,Yue, Xiaoguang,Liang, Chenfeng,Zhao, Jianming,Yu, Wenbo,Zhang, Pengfei
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supporting information
(2021/08/27)
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- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
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With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
- Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
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p. 5936 - 5943
(2021/08/23)
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- Radical Decarboxylative Carbometalation of Benzoic Acids: A Solution to Aromatic Decarboxylative Fluorination
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Abundant aromatic carboxylic acids exist in great structural diversity from nature and synthesis. To date, the synthetically valuable decarboxylative functionalization of benzoic acids is realized mainly by transition-metal-catalyzed decarboxylative cross couplings. However, the high activation barrier for thermal decarboxylative carbometalation that often requires 140 °C reaction temperature limits both the substrate scope as well as the scope of suitable reactions that can sustain such conditions. Numerous reactions, for example, decarboxylative fluorination that is well developed for aliphatic carboxylic acids, are out of reach for the aromatic counterparts with current reaction chemistry. Here, we report a conceptually different approach through a low-barrier photoinduced ligand to metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation strategy, which generates a putative high-valent arylcopper(III) complex, from which versatile facile reductive eliminations can occur. We demonstrate the suitability of our new approach to address previously unrealized general decarboxylative fluorination of benzoic acids.
- Xu, Peng,López-Rojas, Priscila,Ritter, Tobias
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supporting information
p. 5349 - 5354
(2021/05/05)
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- Supported Palladium-Catalyzed Carbonylative Synthesis of Diaryl Ketones from Aryl Bromides and Arylboronic Acids
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A palladium supported on graphitic carbon nitride (Pd/g-C3N4) catalyzed carbonylative reaction of aryl bromides and arylboronic acids by has been developed for the construction of diaryl ketones. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various diaryl ketones in moderate to good yields.
- Xu, Tiefeng,Wang, Qi,Yang, Zeyi,Yi, Lili,Wang, Jian-Shu,Lu, Wangyang,Ying, Jun,Wu, Xiao-Feng
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supporting information
p. 2027 - 2030
(2021/06/21)
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- Feeding Carbonylation with CO2via the Synergy of Single-Site/Nanocluster Catalysts in a Photosensitizing MOF
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Solar-driven carbonylation with CO2 replacing toxic CO as a C1 source is of considerable interest; however it remains a great challenge due to the inert CO2 molecule. Herein, we integrate cobalt single-site and ultrafine CuPd nanocluster catalysts into a
- Fu, Shanshan,Guo, Guang-Chen,Guo, Song,Lu, Tong-Bu,Yao, Shuang,Yuan, Wenjuan,Zhang, Zhi-Ming
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p. 20792 - 20801
(2021/12/14)
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- Ruthenium-Catalyzed Dehydrogenation of Alcohols with Carbodiimide via a Hydrogen Transfer Mechanism
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Ruthenium-catalyzed oxidative dehydrogenation of alcohols using carbodiimide as an efficient hydrogen acceptor has been developed. The protocol exhibits wide substrate scope with good to excellent yields. The results of the kinetic analysis indicated that the reaction mechanism includes the hydrogen transfer process and that the addition of carbodiimide is essential for the reaction system, and the resulting amidine also could react as a hydrogen acceptor.
- Sueki, Shunsuke,Matsuyama, Mizuki,Watanabe, Azumi,Kanemaki, Arata,Katakawa, Kazuaki,Anada, Masahiro
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p. 4878 - 4885
(2020/06/02)
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- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
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A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
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p. 12443 - 12446
(2020/10/30)
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- Synthesis, structure, and characterization of picolyl- and benzyl-linked biphenyl palladium N-heterocyclic carbene complexes and their catalytic activity in acylative cross-coupling reactions
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N-heterocyclic carbene ligands with picolyl (L1H2Br2, L3H2Br2) and benzyl (L2H2Br2, L4H2Br2) linked biphenyl backbone were synthesized and characterized. Their palladium(II) complexes [PdL1]Br2 (1), [PdL2Br2] (2), [PdL3]Br2 (3), and [PdL4Br2] (4) were synthesized by direct method using Pd(OAc)2. All complexes (1–4) were characterized by CHN analysis, electrospray ionization-MS, nuclear magnetic resonance, and single-crystal X-ray diffraction. Molecular structures confirm the distorted square planar geometry around the Pd(II) center. All of them showed good catalytic activity in acylative Suzuki cross coupling of phenyl boronic acid with benzoyl chloride to afford benzophenone in good yields.
- Muniyappan, Nalluchamy,Sabiah, Shahulhameed
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- Palladium-Catalyzed Amide N-C Hiyama Cross-Coupling: Synthesis of Ketones
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N-Acylglutarimides and arylsiloxanes reacted in the presence of Pd(OAc)2/PCy3, Et3N·3HF, and LiOAc to provide the corresponding arylketones in good yields. Aryl-, vinyl-, and alkyl-substituted N-acylglutarimides showed good activity in the coupling reactions of arylsiloxanes. The reaction had a broad substrate scope and showed good functional group tolerance. N-Benzoylsuccinimide and N-protected N-phenylbenzamides showed good activities in coupling reactions with phenylsiloxane. The employment of CuF2 as an activor afforded the decarbonylative products at 160 °C.
- Idris, Muhammad Aliyu,Lee, Sunwoo
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supporting information
p. 9190 - 9195
(2020/11/18)
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- Copper-Catalyzed Oxidative Fragmentation of Alkynes with NFSI Provides Aryl Ketones
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A copper-catalyzed oxidative cleavage reaction of alkynes using NFSI and TBHP was described. Various terminal and internal alkyne substrates were employed to render quick access to aryl ketone products in moderate to good yields. NFSI not only functioned as N-centered radical precursors but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water in the title reactions.
- Chen, Hanfei,Cheng, Hao,Huang, Yifan,Jin, Chaochao,Song, Weihan,Tan, Chen,Tan, Jiajing,Tang, Lin,Yang, Fang,Zhang, Shuaifei
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supporting information
(2020/11/03)
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- Novel synthesis method for aromatic ketone compounds
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The invention discloses a novel method for synthesizing target aromatic ketone compounds by taking alkyne and N-fluorobenzenesulfonamide as initial raw materials of a reaction through a mechanism of catalyzing single electron transfer of alkyne breakage by copper under the action of an oxidizing agent. The method provided by the invention is wide in substrate range, and can construct different substituted aromatic ketone compounds by using fat and aromatic alkyne as substrates. In addition, the method provided by the invention has the advantages of mild reaction conditions, simple operation, product diversity, and capability of realizing large-scale production.
- -
-
Paragraph 0039-0041
(2020/12/08)
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- Silylcarboxylic Acids as Bifunctional Reagents: Application in Palladium-Catalyzed External-CO-Free Carbonylative Cross-Coupling Reactions
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A palladium-catalyzed external-CO-free carbonylative Hiyama-Denmark cross-coupling reaction is presented. The introduction of silylcarboxylic acids as bifunctional reagents (CO and nucleophile source) avoids the need for external gaseous CO and a silylarene coupling partner. The transformation features high functional group tolerance and it is successful with electron-rich, -neutral, and -poor aryl iodides. Stoichiometric studies and control experiments provide insight into the reaction mechanism and support the hypothesized dual role of silylcarboxylic acids. (Figure presented.).
- Li, Xiong,Xu, Jie,Li, Yue,Kramer, S?ren,Skrydstrup, Troels,Lian, Zhong
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p. 4078 - 4083
(2020/07/30)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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- Palladium-Catalyzed Suzuki Coupling of N-Acyloxazolidinones via Selective Cleavage of C–N Bonds
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By implementing a palladium-catalyzed Suzuki coupling reaction of N-acyloxazolidinones with arylboronic acid, we herein report on the preparation of substituted diaryl ketones via selective cleavage of exocyclic C–N Bonds. The reaction was carried out under mild reaction conditions with excellent functional group compatibility in good yields (up to 93 %).
- Jian, Junsheng,He, Zhanyu,Zhang, Yuqi,Liu, Tingting,Liu, Lizhen,Wang, Zijia,Wang, Hui,Wang, Sanyong,Zeng, Zhuo
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supporting information
p. 4176 - 4180
(2020/07/13)
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- Suzuki-Miyaura Cross-Coupling of Amides using Well-Defined, Air-Stable [(PR3)2Pd(II)X2] Precatalysts
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A versatile method for the Suzuki-Miyaura cross-coupling of amides using highly active, well-defined, and air-stable Pd?phosphine precatalysts is reported. Most notably, the method represents the first example of using practical and operationally-simple Pd(II)?phosphine precatalysts in the emerging amide bond cross-coupling manifold. The reactions are efficient at 0.10 mol% loading, furnishing biaryl ketones with high chemoselectivity for N?C(O) bond cleavage. This versatile method enables for the first time to achieve Pd?phosphine-catalyzed cross-coupling of amides at ppm loading. This C?N cross-coupling can be used to efficiently furnish pharmaceutical intermediates by orthogonal Pd-catalyzed cross-couplings. We fully expect that operationally-simple [(PR3)2Pd(II)X2] precatalysts as effective triggers for N?C(O) cross-coupling will be of broad synthetic and catalytic interest. (Figure presented.).
- Li, Guangchen,Ma, Siyue,Szostak, Michal,Zhou, Tongliang
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supporting information
(2020/05/26)
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- Water Phase, Room Temperature, Ligand-Free Suzuki–Miyaura Cross-Coupling: A Green Gateway to Aryl Ketones by C–N Bond Cleavage
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We report herein a green strategy for synthesis of aryl ketones from twisted amides by using Pd(OAc)2 as catalysts. This method shows high functional group tolerance to offer a variety of ketones in good yields under mild conditions (up to 94 %). Notably, this methodology demonstrates the first water phase, room temperature, ligand-free Suzuki–Miyaura coupling through C–N bond cleavage, which is environmentally friendly and might facilitate the development of amide based green chemistry.
- Zhang, Yuqi,Wang, Zijia,Tang, Zhao,Luo, Zhongfeng,Wu, Hongxiang,Liu, Tingting,Zhu, Yulin,Zeng, Zhuo
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p. 1620 - 1628
(2020/03/04)
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- N-Acyl-5,5-Dimethylhydantoins: Mild Acyl-Transfer Reagents for the Synthesis of Ketones Using Pd-PEPPSI or Pd/Phosphine Catalysts
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N-Acyl-hydantoins have emerged as novel acyl-transfer reagents for the synthesis of ketones via selective N-C(O) cleavage. Herein, we report two new protocols for the cross-coupling of N-acyl-5,5-dimethylhydantoins using versatile and readily accessible Pd-PEPPSI or Pd/phosphine catalysts. The acyl Suzuki reactions afford biaryl ketones in good to excellent yields under operationally simple conditions using commercially available, bench- A nd air-stable twisted N-acyl-hydantoins as acyl donors. The method complements and expands on the previous protocol for the cross-coupling of N-acyl-hydantoins (Luo, Z.et al. Org. Process Res. Dev. 2018, 22, 1188).
- Liu, Chengwei,Szostak, Michal,Wang, Chang-An
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p. 1043 - 1051
(2020/07/15)
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- Xantphos-ligated palladium dithiolates: An unprecedented and convenient catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction with high turnover number and turnover frequency
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Xantphos- and dithiolate-ligated macrocyclic palladium complexes as an efficient and stable catalyst for the carbonylative Suzuki–Miyaura cross-coupling reaction have been synthesized. The catalysts were characterized by 1H-nuclear magnetic resonance (NMR), CHNS (carbon, hydrogen, nitrogen, and sulfur) analysis, melting point analysis, and 31P-NMR spectroscopy. Several sensitive functional groups (e.g., –NO2, –F, –Cl, –Br, –NH2, and –CN) on the aromatic ring were well tolerated in the carbonylative Suzuki–Miyaura coupling reaction. The present palladium complexes produce six times higher turnover number (TON) and five times higher turnover frequency (TOF) compared with conventional homogeneous palladium precursors. Maximum TONs in the range of 105 to 106 and TOF in the range of 104 to 105 could be generated by a very low amount of catalyst loading (10–5?mol%).
- Gaikwad, Vinayak V.,Mane, Pravin A.,Dey, Sandip,Bhanage, Bhalchandra M.
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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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- Heterogeneous Suzuki-Miyaura coupling of heteroaryl ester: Via chemoselective C(acyl)-O bond activation
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A site-selective supported palladium nanoparticle catalyzed Suzuki-Miyaura cross-coupling reaction with heteroaryl esters and arylboronic acids as coupling partners was developed. This methodology provides a heterogeneous catalytic route for aryl ketone formation via C(acyl)-O bond activation of esters by successful suppression of the undesired decarbonylation phenomenon. The catalyst can be reused and shows high activity after eight cycles. The XPS analysis of the catalyst before and after the reaction suggested that the reaction might be performed via a Pd0/PdII catalytic cycle that began with Pd0.
- Ma, Hongpeng,Bai, Chaolumen,Bao, Yong-Sheng
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p. 17266 - 17272
(2019/06/24)
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- Magnetically recoverable graphene oxide supported Co@Fe3O4/L-dopa for C-C cross-coupling and oxidation reactions in aqueous medium
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We report the synthesis of inexpensive and environmentally benign cobalt(0) nanoparticles on L-3,4-dihydroxyphenylalanine (L-dopa) functionalized and magnetite (Fe3O4) grafted graphene oxide (Co@GO/Fe3O4/L-dopa) which was fully characterized with different techniques such as Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HR-TEM), X-Ray Photoelectron Spectroscopy (XPS), X-ray Powder Diffraction (XRD), Thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Vibrating Sample Magnetometer (VSM), Carbon Hydrogen Nitrogen (CHN) analysis, Energy Dispersive X-ray (EDX) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Graphene oxide was used as the core material due to its mechanical, electrical and thermal properties. In order to avoid the cumbersome process of separation, magnetite nanoparticles were coated over the graphene oxide. After the successful preparation of graphene oxide based magnetic nanoparticles, L-dopa was grafted over Fe3O4 nanoparticles so as to provide firm anchoring agent for cobalt nanoparticles. Finally, cobalt(0) nanoparticles were immobilized on the developed magnetic support. The catalytic efficiency of the synthesized catalyst was tested for Suzuki cross-coupling and oxidation reactions, usually carried out by precious and expensive second and third row transition metals; products were obtained in good to excellent yields. The synthesized catalyst represents an attractive alternative to conventional catalysts for Suzuki cross-coupling and oxidation reactions, and is recyclable up to five runs.
- Sharma, Harsha,Sharma, Shally,Sharma, Chandan,Paul, Satya,Clark, James H.
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- Method for preparing diarylketone compound through efficient catalysis of pyridine palladium
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According to the invention, a method for preparing a diarylketone compound through efficient catalysis of pyridine palladium is provided, wherein aryl phenylboronic acid, iodobenzene compounds and carbon monoxide are used as raw materials, potassium carbonate or potassium hydroxide is used as alkali, pyridine palladium or 3-chloropyridine palladium is used as a catalyst, and the diaryl compound isprepared at high efficiency and yield. The method provided by the invention has the advantages of small catalyst dosage, high catalytic activity, stability to air, simple operation, short reaction time and high atom economy, opens up a low-cost, green and efficient way for preparation of the diarylketone compound, and has broad application prospects.
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Paragraph 0023; 0045-0049
(2019/12/02)
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- I-Pr2NMgCl·LiCl Enables the Synthesis of Ketones by Direct Addition of Grignard Reagents to Carboxylate Anions
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The direct preparation of ketones from carboxylate anions is greatly limited by the required use of organolithium reagents or activated acyl sources that need to be independently prepared. Herein, a specific magnesium amide additive is used to activate and control the addition of more tolerant Grignard reagents to carboxylate anions. This strategy enables the modular synthesis of ketones from CO2 and the preparation of isotopically labeled pharmaceutical building blocks in a single operation.
- Colas, Kilian,Dos Santos, A. Catarina V. D.,Mendoza, Abraham
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supporting information
(2019/10/08)
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- Selective C?N Bond Cleavage of N-Acylisatins: Towards High Performance Acylation/Arylation/Transamination Reagents
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New multipurpose arylation/acylation/transamination reagents, N-acylisatins, have been developed by selective ‘inside-outside’ C?N bond cleavage under different catalytic conditions. As activated amides, N-acylisatins undergo Rh-catalyzed C?H arylation and Pd-catalyzed acylation by cleavage outside the C?N bond, and the desired biaryls and diaryl ketones were obtained in good to excellent yields. Generally, the combination of N-acylisatins with amines leads to a ring-opening reaction and formation of transamination products in a predictable manner through inside C?N bond cleavage. Interestingly, treatment of N-acylisatins with amines lead to unexpected outer-ring transamination products when CsF is added, which shows that CsF can favor the outside C?N bond cleavage path. Notably, this work presents a new strategy for multiple chemical transformations of a single amide to achieve various products by selective C?N bond cleavage. (Figure presented.).
- Xiong, Li,Deng, Rong,Liu, Tingting,Luo, Zhongfeng,Wang, Zijia,Zhu, Xiao-Feng,Wang, Hui,Zeng, Zhuo
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supporting information
p. 5383 - 5391
(2019/11/03)
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- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
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Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
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p. 16490 - 16494
(2019/11/03)
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- Chemoselective Synthesis of Aryl Ketones from Amides and Grignard Reagents via C(O)-N Bond Cleavage under Catalyst-Free Conditions
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Conversion of a wide range of N-Boc amides to aryl ketones was achieved with Grignard reagents via chemoselective C(O)-N bond cleavage. The reactions proceeded under catalyst-free conditions with different aryl, alkyl, and alkynyl Grignard reagents. α-Ketoamide was successfully converted to aryl diketones, while α,β-unsaturated amide underwent 1,4-addition followed by C(O)-N bond cleavage to provide diaryl propiophenones. N-Boc amides displayed higher reactivity than Weinreb amides with Grignard reagents. A broad substrate scope, excellent yields, and quick conversion are important features of this methodology.
- Sureshbabu, Popuri,Azeez, Sadaf,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 11823 - 11838
(2019/10/02)
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- Sodium Methyl Carbonate as an Effective C1 Synthon. Synthesis of Carboxylic Acids, Benzophenones, and Unsymmetrical Ketones
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Reported is the synthesis of carboxylic acids, symmetrical ketones, and unsymmetrical ketones with selectivity achieved by exploiting the differential reactivity of sodium methyl carbonate with Grignard and organolithium reagents.
- Hurst, Timothy E.,Deichert, Julie A.,Kapeniak, Lucas,Lee, Roland,Harris, Jesse,Jessop, Philip G.,Snieckus, Victor
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supporting information
p. 3882 - 3885
(2019/06/07)
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- Transition-Metal-Free Carbonylative Suzuki-Miyaura Reactions of Aryl Iodides with Arylboronic Acids Using N-Formylsaccharin as CO Surrogate
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Unprecedented, high yielding, transition-metal-free carbonylative Suzuki-Miyaura reactions of aryl iodides with arylboronic acids using N-formylsaccharin as CO surrogate have been developed. Notably, this general protocol was adapted to the synthesis of the triglyceride and cholesterol regulator drug, fenofibrate, and carbon-13 labeled biaryl ketone. (Figure presented.).
- Yu, Dezhong,Xu, Fangning,Li, Dan,Han, Wei
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supporting information
p. 3102 - 3107
(2019/05/21)
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- Oxidative Rearrangement of Primary Amines Using PhI(OAc)2 and Cs2CO3
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An oxidative rearrangement of primary amines mediated by a hypervalent iodine(III) reagent is herein reported. The combination of PhI(OAc)2 and Cs2CO3 proves highly efficient at inducing the direct 1,2-C to N migration of primary amines, which can be applied to the preparation of both acyclic and cyclic amines. A mechanistic study shows that the rearrangement proceeds via a concerted mechanism.
- Yamakoshi, Wataru,Arisawa, Mitsuhiro,Murai, Kenichi
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supporting information
(2019/05/08)
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- Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
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An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
- Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
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supporting information
(2019/05/08)
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- Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
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An intermolecular coupling of primary alcohols and organotriflates has been developed to provide ketones by the action of a Ni(0) catalyst. This oxidative transformation is proposed to occur by the union of three distinct catalytic cycles. Two competitive oxidation processes generate aldehyde in situ via hydrogen transfer oxidation or (pseudo)dehalogenation pathways. As aldehyde forms, a Ni-catalyzed carbonyl-Heck process enables formation of the key carbon-carbon bond. The utility of this rare alcohol to ketone transformation is demonstrated through the synthesis of diverse complex and bioactive molecules.
- Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
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supporting information
p. 6869 - 6874
(2019/05/10)
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- Well-Defined, Air-Stable, and Readily Available Precatalysts for Suzuki and Buchwald-Hartwig Cross-coupling (Transamidation) of Amides and Esters by N-C/O-C Activation
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A general class of well-defined, air-stable, and readily available Pd(II)-NHC precatalysts (NHC = N-heterocyclic carbene) for Suzuki and Buchwald-Hartwig cross-coupling of amides (transamidation) and esters by selective N-C/O-C cleavage is reported. Since these precatalysts are highly active and the easiest to synthesize, the study clearly suggests that [Pd(NHC)(acac)Cl] should be routinely included during the development of new cross-coupling methods. An assay for in situ screening of NHC salts in this cross-coupling manifold is presented.
- Zhou, Tongliang,Li, Guangchen,Nolan, Steven P.,Szostak, Michal
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supporting information
p. 3304 - 3309
(2019/05/10)
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- Decarboxylation with Carbon Monoxide: The Direct Conversion of Carboxylic Acids into Potent Acid Triflate Electrophiles
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We report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.
- Kinney, R. Garrison,Arndtsen, Bruce A.
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supporting information
p. 5085 - 5089
(2019/04/01)
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- Continuous flow synthesis of diaryl ketones by coupling of aryl Grignard reagents with acyl chlorides under mild conditions in the ecofriendly solvent 2-methyltetrahydrofuran
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An efficient continuous flow sequential synthesis of diaryl ketones was achieved by coupling of aryl Grignard reagents with acyl chlorides in the bio-derived “green” solvent 2-methyltetrahydrofuran (2-MeTHF) under mild reaction conditions (ambient temperature, 1 hour), allowing a safe and on-demand generation of 2-(3-benzoylphenyl)propionitrile with a productivity of 3.16 g hour?1
- Zhang, Chuan-Tao,Zhu, Rui,Wang, Zheng,Ma, Bing,Zajac, Adrian,Smiglak, Marcin,Xia, Chun-Nian,Castle, Steven L.,Wang, Wen-Long
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p. 2199 - 2204
(2019/01/26)
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- Ligand-free Palladium-Catalyzed Carbonylative Suzuki Coupling of Aryl Iodides in Aqueous CH3CN with Sub-stoichiometric Amount of Mo(CO)6 as CO Source
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A new method for the synthesis of diaryl and heterodiaryl ketones has been established based on the palladium-catalyzed carbonylative Suzuki coupling approach with sub-stoichiometric Mo(CO)6 as CO source. Using 0.5 mol% of Pd(TFA)2 as catalyst, 0.5 equivalent of Mo(CO)6 as solid carbonyl reagent and 3 equivalent of K3PO4 as base, a wide range of functionalized (hetero)aryl iodides and (hetero)aryl boronic acids could smoothly proceed the carbonylative cross-coupling reaction in aqueous CH3CN at 50 °C, affording the corresponding ketones in good to excellent yields. The newly developed method was easy to operate under mild conditions with high efficiency. (Figure presented.).
- Sun, Nan,Sun, Qingxia,Zhao, Wei,Jin, Liqun,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan
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p. 2117 - 2123
(2019/03/28)
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- Efficient construction of C–C bonds from aryl halides/aryl esters with arylboronic acids catalysed by palladium(II) thiourea complexes
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A new set of palladium(II) complexes comprising phenyl(thiazolyl)thiourea ligands have been successfully synthesized and characterized with the aid of analytical as well as spectral (IR, UV–visible and NMR) methods. A distorted square-planar geometry with N^S coordination mode of thiourea ligands in the new palladium complexes was corroborated by single-crystal X-ray diffraction methods. Interestingly, the palladium(II) thiourea complexes showed the highest catalytic activity with 0.1 mol% catalyst loading in Suzuki–Miyaura cross-coupling reactions utilizing a range of aryl bromides/unactivated aryl chlorides with arylboronic acids as coupling partners in aqueous–organic media. Syntheses of diaryl ketones using aryl esters and arylboronic acids as coupling partners were also achieved with low catalyst loading within 20 h. The potential of our catalyst was demonstrated by its wide substrate scope, low catalyst loadings and high isolated yield. Moreover, the influences of key parameters like solvent, base, temperature and catalyst loading were also investigated.
- Thimma Sambamoorthy, Manikandan,Rengan, Ramesh,Jan Grzegorz, Malecki
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