- Electrochemical benzylic oxidation of C-H bonds
-
Oxidized products have become increasingly valuable as building blocks for a wide variety of different processes and fine chemistry, especially in the benzylic position. We report herein a sustainable protocol for this transformation through C-H functionalization and is performed using electrochemistry as the main power source and tert-butyl hydroperoxide as the radical source for the C-H abstraction. The temperature conditions reported here do not increase above 50 °C and use an aqueous-based medium. A broad substrate scope is explored, along with bioactive molecules, to give comparable and increased product yields when compared to prior reported literature without the use of electrochemistry.
- Marko, Jason A.,Durgham, Anthony,Bretz, Stacey Lowery,Liu, Wei
-
-
Read Online
- Phosphine-free pincer-ruthenium catalyzed biofuel production: High rates, yields and turnovers of solventless alcohol alkylation
-
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
- Das, Babulal,Das, Kanu,Kumar, Akshai,Srivastava, Hemant Kumar,Yasmin, Eileen
-
p. 8347 - 8358
(2020/12/31)
-
- Visible-Light-Promoted Photocatalyst-Free Hydroacylation and Diacylation of Alkenes Tuned by NiCl2·DME
-
Herein, we describe a visible light-promoted hydroacylation strategy that facilitates the preparation of ketones from alkenes and 4-acyl-1,4-dihydropyridines via an acyl radical addition and hydrogen atom transfer pathway under photocatalyst-free conditions. The efficiency was highlighted by wide substrate scope, good to high yields, successful scale-up experiments, and expedient preparation of highly functionalized ketone derivatives. In addition, this protocol allows for the synthesis of 1,4-dicarbonyl compounds through alkene diacylation in the presence of NiCl2·DME.
- Zhao, Xinxin,Li, Bing,Xia, Wujiong
-
p. 1056 - 1061
(2020/02/15)
-
- Method for synthesizing alpha-alkylated ketone in water
-
The invention discloses a method for synthesizing alpha-alkylated ketone in water. The method comprises the following steps: adding ketone, compound alcohol, a transition metal iridium catalyst, an alkali and a solvent, namely water into a reaction container, carrying out a reflux reaction on a reaction mixture in the air for several hours, carrying out cooling to room temperature, carrying out rotary evaporation to remove the solvent, and carrying out column separation (ethyl acetate/petroleum ether) to obtain a target compound, namely alpha-alkylated ketone. A reaction equivalent substrate is used in the reaction process, so raw material waste is avoided; equivalent alkali is used, so better environmental protection performance is obtained; water reflux reaction conditions are milder; and non-toxic and harmless pure water is used as the solvent in the reaction, only water is generated as a by-product, so atom reaction economy is high, and the requirements of green chemistry are met.
- -
-
Paragraph 0087-0091
(2020/08/22)
-
- The α-alkylation of ketones with alcohols in pure water catalyzed by a water-soluble Cp?Ir complex bearing a functional ligand
-
A water-soluble dinuclear Cp?Ir complex bearing 4,4′,6,6′-tetrahydroxy-2,2′-bipyrimidine as a bridging ligand was found to be a highly effective catalyst for the α-alkylation of ketones with alcohols in pure water. In the presence of catalyst (0.5 mol%), a series of desirable products were obtained with high reaction economy under environmentally benign conditions. The importance of the hydroxy group in the ligand for catalytic hydrogen transfer was confirmed by mechanism experiments. Furthermore, the application of this catalytic system for the synthesis of a biologically active molecule donepezil in pure water has been accomplished. Notably, this research would facilitate the progress of C-C bond-forming reactions in water catalyzed by water-soluble metal-ligand bifunctional catalysts.
- Meng, Chong,Xu, Jing,Tang, Yawen,Ai, Yao,Li, Feng
-
p. 14057 - 14065
(2019/09/18)
-
- Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones
-
Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well as alcohols yielded the monoselective ketones in up to 90% yield. The catalytic protocol was successfully applied in to a gram-scale synthesis. For a practical utility, applications of a steroid derivative, oleyl alcohol, and naproxen alcohol were employed. Preliminary catalytic investigations involving the isolation of a Ni intermediate and defined Ni-H species as well as a series of deuterium-labeling experiments were performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
-
p. 769 - 779
(2019/01/24)
-
- Photocatalytic decarboxylative coupling between α-oxocarboxylicacids and alkenes
-
Photocatalytic decarboxylative cross-coupling which achieves the derivatization of widespread organic acids has become a hot topic in organic synthesis. As special acids, α-oxocarboxylicacids show the great potential in running decarboxylation to construc
- Chen, Ziyue,Lu, Fangling,Yuan, Feng,Sun, Juanjuan,Du, Linyu,Li, Zhen,Gao, Meng,Shi, Renyi,Lei, Aiwen
-
p. 1497 - 1500
(2019/11/16)
-
- A from the aromatic acid directly preparing aromatic ketone method (by machine translation)
-
A process for preparing aryl ketone of the method, it is in order to aromatic carboxylic acid (ArCOOH) and olefin as raw materials, triphenylphosphine as a deoxidizing agent, under the irradiation of the blue lamp, in dichloromethane and water solution, under argon atmosphere, in the presence of a small amount of potassium phosphate, in order to [Ir (dF (CF3 ) Ppy)2 (Dtbbpy)] PF6 As the photocatalyst, get the aromatic compounds. The method easily available raw materials, mild reaction conditions, wide adaptability. (by machine translation)
- -
-
Paragraph 0024; 0025
(2019/01/06)
-
- Vinylpyridines as Building Blocks for the Photocatalyzed Synthesis of Alkylpyridines
-
The photocatalyzed addition of several hydrogen donors (ethers, aldehydes, alkanes, amides) onto vinylpyridines was achieved. This approach provided access to alkylpyridines, which are important building blocks for the preparation of compounds with biological activity. The strategy was very simple and straightforward because it required only a small amount of a cheap decatungstate salt as photocatalyst. As an added advantage, the reaction could be performed under sunlight irradiation as well as under flow conditions.
- Capaldo, Luca,Fagnoni, Maurizio,Ravelli, Davide
-
supporting information
p. 6527 - 6530
(2017/05/15)
-
- Transition-Metal-Free Self-Hydrogen-Transferring Allylic Isomerization
-
Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the SRN1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
- Zheng, Hong-Xing,Xiao, Zu-Feng,Yao, Chuan-Zhi,Li, Qiang-Qiang,Ning, Xiao-Shan,Kang, Yan-Biao,Tang, Yong
-
supporting information
p. 6102 - 6105
(2016/01/09)
-
- Direct α-alkylation of ketones with primary alcohols catalyzed by iridium-CNP complex
-
The α-alkylation of ketones with primary alcohols was realized by CC cross-coupling with iridium-CNP complexes as catalyst. This reaction proceeds via dehydrogenation reactions, aldol condensation, and hydrogenation using the borrowed hydrogen atoms from alcohols. The pyridyl methanols and other heterocyclic substituted methanols, especially alkyl alcohols, were also suitable for this transformation.
- Wang, Dawei,Zhao, Keyan,Ma, Piming,Xu, Chongying,Ding, Yuqiang
-
supporting information
p. 7233 - 7235
(2015/01/09)
-
- Efficient ruthenium-catalyzed α-alkylation of ketones using pyridyl methanols
-
By employing an easily available [Ru(p-cymene)Cl2] 2/Xantphos/t-BuOK catalyst system, the α-alkylation of ketones was demonstrated by using pyridyl methanol as the alkylating reagents. The synthetic protocol allows synthesizing a wid
- Yan, Feng-Xia,Zhang, Min,Wang, Xiao-Ting,Xie, Feng,Chen, Meng-Meng,Jiang, Huanfeng
-
supporting information
p. 1193 - 1198
(2014/02/14)
-
- C-C cross-coupling of primary and secondary benzylic alcohols using supported gold-based bimetallic catalysts
-
Clean alcohol-alcohol cross-coupling: A clean and efficient one-pot direct C-C cross-coupling of equimolar amounts of primary and secondary alcohols by a facile hydrogen autotransfer pathway is achieved over a robust and easily recovered hydrotalcite-supported Au-Pd bimetallic catalyst system. A variety of primary and secondary alcohols have been selectively converted into the corresponding b-alkylated ketones in good yields.
- Liu, Xiang,Ding, Ran-Sheng,He, Lin,Liu, Yong-Mei,Cao, Yong,He, He-Yong,Fan, Kang-Nian
-
p. 604 - 608
(2013/07/27)
-
- Copper-catalyzed formal C-N bond cleavage of aromatic methylamines: Assembly of pyridine derivatives
-
An efficient copper-catalyzed C-N bond cleavage of aromatic methylamines was developed to construct pyridine derivatives. With neat conditions and facile operation, the fragment-assembling strategy affords a broad range of 2,4,6-trisubstituted pyridines in up to 95% yield from simple and readily available starting materials. Interestingly, when pyridin-2-yl methylamine was employed as the substrate, α-alkylation reaction of ketones readily occurred to give β-(pyridin-2-yl) ketones instead of the 2,4,6-trisubstituted pyridines.
- Huang, Huawen,Ji, Xiaochen,Wu, Wanqing,Huang, Liangbin,Jiang, Huanfeng
-
p. 3774 - 3782
(2013/06/05)
-
- Organic ligand-free alkylation of amines, carboxamides, sulfonamides, and ketones by using alcohols catalyzed by heterogeneous Ag/Mo oxides
-
Complicated and expensive organic ligands are normally essential in fine chemical synthesis at preparative or industrial levels. The synthesis of fine chemicals by using heterogeneous catalyst systems without additive organic ligand is highly desirable but severely limited due to their poor generality and rigorous reaction conditions. Here, we show the results of carbon-nitrogen or carbon-carbon bond formation catalyzed by an Ag/Mo hybrid material with specific Ag6Mo10O33 crystal structure. 48 nitrogen- or oxygen-containing compounds, that is, amines, carboxamides, sulfonamides, and ketones, were successfully synthesized through a borrowing-hydrogen mechanism. Up to 99% isolated yields were obtained under relatively mild conditions without additive organic ligand. The catalytic process shows promise for the efficient and economic synthesis of amine, carboxamide, sulfonamide, and ketone derivatives because of the simplicity of the system and ease of operation. Copyright
- Cui, Xinjiang,Zhang, Yan,Shi, Feng,Deng, Youquan
-
supporting information; experimental part
p. 1021 - 1028
(2011/03/20)
-
- Generation of β-keto radicals from cyclopropanols catalyzed by AgNO3
-
Various β-keto radicals are generated from cyclopropanols by treatment with a catalytic amount of AgNO3 and (NH4) 2S2O8 as a reoxidant in the presence of pyridine. Thus, generated β-keto radicals react with alkenes to yield addition products. Copyright
- Chiba, Shunsuke,Cao, Zhengyan,El Bialy, Serry Atta Atta,Narasaka, Koichi
-
-
- RECYCLIZATION OF 2-(2-ACYLETHYL)PYRIDINIUM SALTS
-
Recyclization of 2-(2-acylethyl)pyridinium salts on treatment with nucleophiles may occur in different ways, to give heterocyclic compounds of various classes, namely indoles (the Kost-Sagitullin reaction products), 4-aminoindoles, and 3-hydroxy-1,2,3,4-tetrahydroquinolines, the formation of which constitute novel reactions in the recyclization of pyridinium salts.
- Terenin, V. I.,Rumyantsev, A. N.,Nosyrev, P. V.,Gromov, S. P.,Bundel', Yu. G.
-
p. 1016 - 1022
(2007/10/02)
-