39976-56-2Relevant academic research and scientific papers
Nickel-catalyzed α-alkylation of ketones with benzyl alcohols
Wu, Di,Wang, Yubin,Li, Min,Shi, Lei,Liu, Jichang,Liu, Ning
, (2021/11/04)
We reported an efficient method for α-alkylation of ketones with benzyl alcohols using the pyridine-bridged pincer-type N-heterocyclic carbenes nickel complexes as catalysts. A wide range of ketones and benzyl alcohols were efficiently converted into various alkylated products in moderate to high yields. In addition, these nickel complexes were also successfully applied for the synthesis of a wide range of quinoline derivatives.
The Heck reaction of allylic alcohols catalysed by an N-heterocyclic carbene-Pd(ii) complex and toxicity of the ligand precursor for the marine benthic copepod: Amphiascoides atopus
Cárdenas, Jorge,Gómez, Samuel,García-Ríos, Eréndira,Gavi?o, Ruben,López-Torres, Adolfo,Morales-Serna, Francisco Neptalí,Morales-Serna, José Antonio,Puello-Cruz, Ana C.,Rios-Ruiz, Lucero
, p. 20278 - 20284 (2021/06/28)
The palladium-catalysed reaction of aryl halides and allylic alcohols is an attractive method for obtaining α,β-unsaturated aldehydes and ketones, which represent key intermediates in organic synthesis. In this context, a 1,2,3-triazol-5-ylidene (aNHC)-based palladium(ii) complex formed in situ has been found to be a selective catalyst for the syntheses of building blocks from the corresponding aryl halides and allylic alcohols, with yields ranging from 50% to 90%. The lack of toxic effects of the ligand precursor (1,2,3-triazolium salt) of the palladium(ii) complex for the harpacticoid copepod Amphiascoides atopus allowed us to contrast the efficiency of the catalytic system with the potential impact of the principal waste chemical in global aquatic ecosystems, which has not been previously addressed.
Phosphine-free pincer-ruthenium catalyzed biofuel production: High rates, yields and turnovers of solventless alcohol alkylation
Das, Babulal,Das, Kanu,Kumar, Akshai,Srivastava, Hemant Kumar,Yasmin, Eileen
, p. 8347 - 8358 (2020/12/31)
Phosphine-free pincer-ruthenium carbonyl complexes based on bis(imino)pyridine and 2,6-bis(benzimidazole-2-yl) pyridine ligands have been synthesized. For the β-alkylation of 1-phenyl ethanol with benzyl alcohol at 140 °C under solvent-free conditions, (Cy2NNN)RuCl2(CO) (0.00025 mol%) in combination with NaOH (2.5 mol%) was highly efficient (ca. 93% yield, 372?000 TON at 12?000 TO h-1). These are the highest reported values hitherto for a ruthenium based catalyst. The β-alkylation of various alcohol combinations was accomplished with ease which culminated to give 380?000 TON at 19?000 TO h-1 for the β-alkylation of 1-phenyl ethanol with 3-methoxy benzyl alcohol. DFT studies were complementary to mechanistic studies and indicate the β-hydride elimination step involving the extrusion of acetophenone to be the overall RDS. While the hydrogenation step is favored for the formation of α-alkylated ketone, the alcoholysis step is preferred for the formation of β-alkylated alcohol. The studies were extended for the upgradation of ethanol to biofuels. Among the pincer-ruthenium complexes based on bis(imino)pyridine, (Cy2NNN)RuCl2(CO) provided high productivity (335 TON at 170 TO h-1). Sterically more open pincer-ruthenium complexes such as (Bim2NNN)RuCl2(CO) based on the 2,6-bis(benzimidazole-2-yl) pyridine ligand demonstrated better reactivity and gave not only good ethanol conversion (ca. 58%) but also high turnovers (ca. 2100) with a good rate (ca. 710 TO h-1). Kinetic studies indicate first order dependence on concentration of both the catalyst and ethanol. Phosphine-free catalytic systems operating with unprecedented activity at a very low base loading to couple lower alcohols to higher alcohols of fuel and pharmaceutical importance are the salient features of this report. This journal is
Tuning the Product Selectivity of the α-Alkylation of Ketones with Primary Alcohols using Oxidized Titanium Nitride Photocatalysts and Visible Light
Li, Peifeng,Su, Haijia,Xiao, Gang,Zhao, Yilin
, p. 3640 - 3649 (2020/04/09)
The direct α-alkylation of ketones with alcohol to synthesize important α-alkylated ketones and enones is an attractive procedure for C-C bond formation. High reaction temperatures are always needed for heterogeneous catalysis using non-noble metals, and switching product selectivity in one catalysis system remains a great challenge. In the present study, a visible-light-driven procedure for this reaction is proposed, using oxidized TiN photocatalysts under mild conditions, whereby the product selectivity can be well-tuned. Oxidized TiN photocatalysts with tunable surface N/O ratios were successfully synthesized through the facile and flexible thermal oxidation treatment of low-cost TiN nanopowder. The α-alkylation of acetophenone with benzyl alcohol to form the two important compounds chalcone and dihydrochalcone occurred even at room temperature and almost complete conversion was achieved at 100 °C under visible light. The proportion of the two products can be well-tuned by switching the surface N/O ratio of the synthesized photocatalysts. Visible light is demonstrated to affect the surface N/O ratio of the photocatalysts and contribute to tuning the product selectivity. Light intensity and action spectrum study proves that the generation of energetic charge carriers results in the observed activities under visible light, based on interband transitions of TiN or the ligand-to-metal charge transfer (LMCT) effect of the surface complex formed on TiO2. Thermal energy can be coupled with light energy within this photocatalytic system, which will facilitate the full use of solar energy. Different sequential reaction mechanisms on TiN and TiO2 are proposed to be responsible for the tunable product selectivity. The wide reaction scope, the fine conversion at a low light intensity, and the favorable reusability of photocatalysts prove the great application potential of this visible-light-driven procedure for the α-alkylation of ketones with primary alcohols.
Cyclometalated Ruthenium Pincer Complexes as Catalysts for the α-Alkylation of Ketones with Alcohols
Piehl, Patrick,Amuso, Roberta,Alberico, Elisabetta,Junge, Henrik,Gabriele, Bartolo,Neumann, Helfried,Beller, Matthias
supporting information, p. 6050 - 6055 (2020/03/13)
Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. By replacing CO and H? as ancillary ligands in such complexes, additional electronic and steric modifications of this topical class of catalysts are possible. The advantages of the new catalysts are demonstrated in the general α-alkylation of ketones with alcohols following a hydrogen autotransfer protocol. Herein, various aliphatic and benzylic alcohols were applied as green alkylating agents for ketones bearing aromatic, heteroaromatic or aliphatic substituents as well as cyclic ones. Mechanistic investigations revealed that during catalysis, Ru carboxylate complexes are predominantly formed whereas neither the PNP nor the CN ligand are released from the catalyst in significant amounts.
Sustainable and Selective Alkylation of Deactivated Secondary Alcohols to Ketones by Non-bifunctional Pincer N-heterocyclic Carbene Manganese
Lan, Xiao-Bing,Ye, Zongren,Liu, Jiahao,Huang, Ming,Shao, Youxiang,Cai, Xiang,Liu, Yan,Ke, Zhuofeng
, p. 2557 - 2563 (2020/05/04)
A sustainable and green route to access diverse functionalized ketones via dehydrogenative–dehydrative cross-coupling of primary and secondary alcohols is demonstrated. This borrowing hydrogen approach employing a pincer N-heterocyclic carbene Mn complex displays high activity and selectivity. A variety of primary and secondary alcohols are well tolerant and result in satisfactory isolated yields. Mechanistic studies suggest that this reaction proceeds via a direct outer-sphere mechanism and the dehydrogenation of the secondary alcohol substrates plays a vital role in the rate-limiting step.
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
supporting information, (2019/05/08)
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.
Ketone Synthesis by a Nickel-Catalyzed Dehydrogenative Cross-Coupling of Primary Alcohols
Verheyen, Thomas,Van Turnhout, Lars,Vandavasi, Jaya Kishore,Isbrandt, Eric S.,De Borggraeve, Wim M.,Newman, Stephen G.
supporting information, p. 6869 - 6874 (2019/05/10)
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.
Controlling the selectivity and efficiency of the hydrogen borrowing reaction by switching between rhodium and iridium catalysts
Wang, Danfeng,McBurney, Roy T.,Pernik, Indrek,Messerle, Barbara A.
supporting information, p. 13989 - 13999 (2019/10/01)
The catalytic alkylation of ketones with alcohols via the hydrogen borrowing methodology (HB) has the potential to be a highly efficient approach for forming new carbon-carbon bonds. However, this transformation can result in more than one product being formed. The work reported here utilises bidentate triazole-carbene ligated iridium and rhodium complexes as catalysts for the selective formation of alkylated ketone or alcohol products. Switching from an iridium centre to a rhodium centre in the complex resulted in significant changes in product selectivity. Other factors-base, base loading, solvent and reaction temperature-were also investigated to tune the selectivity further. The optimised conditions were used to demonstrate the scope of the reaction across 17 ketones and 14 alcohols containing a variety of functional groups. A series of mechanistic investigations were performed to probe the reasons behind the product selectivity, including kinetic and deuterium studies.
Nickel-Catalyzed Coupling of Arylzinc Halides with Thioesters
Gehrtz, Paul H.,Kathe, Prasad,Fleischer, Ivana
supporting information, p. 8774 - 8778 (2018/06/26)
The Pd-catalyzed Fukuyama reaction of thioesters with organozinc reagents is a mild, functional-group-tolerant method for acylation chemistry. Its Ni-catalyzed variant might be a sustainable alternative to expensive catalytic Pd sources. We investigated the reaction of S-ethyl thioesters with aryl zinc halides with hetero- and homotopic Ni precatalysts and several ligands. The results show that both homo- and heterotopic species may contribute to catalysis. The substrate scope using an operationally homogeneous defined Ni complex was established. Acyl radicals are postulated as short-lived intermediates.
