cas 1883-32-5, 2,2-Diphenylethanol | Articles data

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A practical decarboxylative hydroxylation of carboxylic acids
Irradiation of esters of N-hydroxy-2-thiazolinethione under air or oxygen at room temperature in the presence of tert-dodecanethiol affords the corresponding nor-alcohols after a reductive work-up.
Barton, Derek H. R.,Gero, Stephane D.,Holliday, Pascale,Quiclet-Sire, Beatrice,Zard, Samir Z.
p. 6751 - 6756
(1998)
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Micovic et al.
p. 340
(1957)
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Method for activation and recycling of trityl resins
This note describes a rapid and mild strategy for the loading of alcohols and anilines onto a polystyrene triphenylmethyl (trityl) resin. High loadings were obtained in a matter of minutes by treating resin-bound trityl chloride with triethyloxonium tetrafluoroborate followed by alcohols or anilines. Yields were comparable or better than known literature methods. Recycling of the recovered resin was also possible using the developed method.
Redwan, Itedale Namro,Gr?tli, Morten
p. 7071 - 7075
(2012)
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A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
Huang, Binbin,Guo, Lin,Xia, Wujiong
supporting information
p. 2095 - 2103
(2021/03/26)

Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
Reduction reactions of unsaturated compounds are fundamental transformations in synthetic chemistry. In this context, the reduction of polarized double bonds such as carbonyl or C=C motifs can be achieved by hydrogenation reactions. We describe here a highly chemoselective Mn(I)-based PNP pincer catalyst for the hydrosilylation of aldehydes and ketones employing polymethylhydrosiloxane (PMHS) as inexpensive hydrogen donor. Graphic abstract: [Figure not available: see fulltext.]
Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
p. 635 - 639
(2021/06/17)

Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
Lambert, Tristan H.,Steiniger, Keri A.
p. 8013 - 8017
(2021/10/25)

Uranyl(VI) Triflate as Catalyst for the Meerwein-Ponndorf-Verley Reaction
Catalytic transformation of oxygenated compounds is challenging in f-element chemistry due to the high oxophilicity of the f-block metals. We report here the first Meerwein-Ponndorf-Verley (MPV) reduction of carbonyl substrates with uranium-based catalysts, in particular from a series of uranyl(VI) compounds where [UO2(OTf)2] (1) displays the greatest efficiency (OTf = trifluoromethanesulfonate). [UO2(OTf)2] reduces a series of aromatic and aliphatic aldehydes and ketones into their corresponding alcohols with moderate to excellent yields, using iPrOH as a solvent and a reductant. The reaction proceeds under mild conditions (80 °C) with an optimized catalytic charge of 2.3 mol % and KOiPr as a cocatalyst. The reduction of aldehydes (1-10 h) is faster than that of ketones (>15 h). NMR investigations clearly evidence the formation of hemiacetal intermediates with aldehydes, while they are not formed with ketones.
Kobylarski, Marie,Monsigny, Louis,Thuéry, Pierre,Berthet, Jean-Claude,Cantat, Thibault
supporting information
p. 16140 - 16148
(2021/11/01)

Catalytic C-C coupling of diazo compounds with arylboronic acids: Using surface modified sewage sludge as catalyst
A green, mild and efficient synthesis of diarylmethines using sewage sludge-derived carbonaceous materials (SW) by perchloric acid catalyzed coupling reactions between diazo compounds and arylboronic acids was developed. The reaction shows a high level of functional tolerance and a broad substrate scope. Furthermore, the highly selective 1,2-alkyl shift products were furnished through the sterically demanding R4, R5 migration of diazo compounds (3-diazochromanone). The structures of 1,2-shift products have been further confirmed by single-crystal X-ray analysis. Significantly, the synthesis of the core structures of darifenacin (a clinical drug for overactive bladder syndrome, OAB) and diclofensine (a stimulant drug showing antidepressant and monoamine reuptake inhibitor activity) further demonstrated the efficacy and synthetic potential of this method. This journal is
Huang, Fei,Huang, He,Hughes, Timothy,Xie, Yuxing,Xu, Jun,Yu, Yang,Zhang, Zhipeng
supporting information
p. 4165 - 4173
(2020/07/14)

Continuous-Flow Amide and Ester Reductions Using Neat Borane Dimethylsulfide Complex
Reductions of amides and esters are of critical importance in synthetic chemistry, and there are numerous protocols for executing these transformations employing traditional batch conditions. Notably, strategies based on flow chemistry, especially for amide reductions, are much less explored. Herein, a simple process was developed in which neat borane dimethylsulfide complex (BH3?DMS) was used to reduce various esters and amides under continuous-flow conditions. Taking advantage of the solvent-free nature of the commercially available borane reagent, high substrate concentrations were realized, allowing outstanding productivity and a significant reduction in E-factors. In addition, with carefully optimized short residence times, the corresponding alcohols and amines were obtained in high selectivity and high yields. The synthetic utility of the inexpensive and easily implemented flow protocol was further corroborated by multigram-scale syntheses of pharmaceutically relevant products. Owing to its beneficial features, including low solvent and reducing agent consumption, high selectivity, simplicity, and inherent scalability, the present process demonstrates fewer environmental concerns than most typical batch reductions using metal hydrides as reducing agents.
?tv?s, Sándor B.,Kappe, C. Oliver
p. 1800 - 1807
(2020/02/27)

Method for preparation of aromatic alcohol by photocatalysis of aromatic aldehyde conversion
The invention relates to a method for preparation of aromatic alcohol by photocatalysis of aromatic aldehyde conversion. By means of a photocatalyst, under the conditions of illumination and inert gas, fatty alcohol is adopted as a proton donor for reduction reaction on aromatic aldehyde to obtain corresponding aromatic alcohol. Fatty alcohol is used as the proton donor, and light energy is used as the energy source to promote high-conversion-rate and high-selectivity synthesis of a series of aromatic alcohol compounds from aromatic aldehyde, the method has universal applicability, and is expected to realize industrial production; and the reaction process is green and environment-friendly, low in cost, easy to operate, short in reaction period, high in conversion rate and good in selectivity.
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(2020/04/17)

Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
supporting information
p. 14286 - 14294
(2020/09/15)

Erbium-Catalyzed Regioselective Isomerization-Cobalt-Catalyzed Transfer Hydrogenation Sequence for the Synthesis of Anti-Markovnikov Alcohols from Epoxides under Mild Conditions
Herein, we report an efficient isomerization-transfer hydrogenation reaction sequence based on a cobalt pincer catalyst (1 mol %), which allows the synthesis of a series of anti-Markovnikov alcohols from terminal and internal epoxides under mild reaction conditions (≤55 °C, 8 h) at low catalyst loading. The reaction proceeds by Lewis acid (3 mol % Er(OTf)3)-catalyzed epoxide isomerization and subsequent cobalt-catalyzed transfer hydrogenation using ammonia borane as the hydrogen source. The general applicability of this methodology is highlighted by the synthesis of 43 alcohols from epoxides. A variety of terminal (23 examples) and 1,2-disubstituted internal epoxides (14 examples) bearing different functional groups are converted to the desired anti-Markovnikov alcohols in excellent selectivity and yields of up to 98%. For selected examples, it is shown that the reaction can be performed on a preparative scale up to 50 mmol. Notably, the isomerization step proceeds via the most stable carbocation. Thus, the regiochemistry is controlled by stereoelectronic effects. As a result, in some cases, rearrangement of the carbon framework is observed when tri-and tetra-substituted epoxides (6 examples) are converted. A variety of functional groups are tolerated under the reaction conditions even though aldehydes and ketones are also reduced to the respective alcohols under the reaction conditions. Mechanistic studies and control experiments were used to investigate the role of the Lewis acid in the reaction. Besides acting as the catalyst for the epoxide isomerization, the Lewis acid was found to facilitate the dehydrogenation of the hydrogen donor, which enhances the rate of the transfer hydrogenation step. These experiments additionally indicate the direct transfer of hydrogen from the amine borane in the reduction step.
Liu, Xin,Longwitz, Lars,Spiegelberg, Brian,T?njes, Jan,Beweries, Torsten,Werner, Thomas
p. 13659 - 13667
(2020/11/30)

A is by aromatic carboxylic acid non-catalytic reaction of alcohol compound (by machine translation)
The present invention discloses a non-catalytic reaction of the aromatic carboxylic acid preparation of alcohol compound. In an inert gas atmosphere, after dehydration and deoxidation treatment of the reaction bottle [...] borane and carboxylic acid stirring and mixing, reaction 6 - 12 hours to obtain borate, further hydrolyzed into alcohol; said carboxylic acid is benzoic acid, 4 - bromobenzoic acid, 4 - fluoro benzoic acid, 1 - naphthoic acid, 2 - methoxybenzene formic acid and the like. The invention for the first time in the absence of catalyst under the conditions of high-efficiently using carboxylic acid with borane generating borohydrite reaction, carbonyl compound with borane generating borohydrite reaction preparation borate, further hydrolysis alcohol, provides new programme. (by machine translation)
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Paragraph 0027

(2019/04/17)

Selective Hydroboration of Carboxylic Acids with a Homogeneous Manganese Catalyst
Catalytic reduction of carboxylic acid to the corresponding alcohol is a challenging task of great importance for the production of a variety of value-added chemicals. Herein, a manganese-catalyzed chemoselective hydroboration of carboxylic acids has been developed with a high turnover number (>99?000) and turnover frequency (>2000 h-1) at 25 °C. This method displayed tolerance of electronically and sterically differentiated substrates with high chemoselectivity. Importantly, aliphatic long-chain fatty acids, including biomass-derived compounds, can efficiently be reduced. Mechanistic studies revealed that the reaction occurs through the formation of active manganese-hydride species via an insertion and bond metathesis type mechanism.
Barman, Milan K.,Das, Kuhali,Maji, Biplab
p. 1570 - 1579
(2019/01/30)

Method for preparing alcoholic compound from anilino lithium compound as catalyst
The invention relates to an application of an anilino lithium compound, in particular to a method for preparing an alcoholic compound from the anilino lithium compound as a catalyst. The catalyst, borane and carboxylic acid are stirred and mixed uniformly, subjected to a reaction and exposed to air to terminate the reaction, a reacted liquid is subjected to reduced-pressure treatment for solvent removal, silica gel and methanol are added, and the alcoholic compound is obtained by hydrolysis. The anilino lithium compound can perform high-activity catalysis on the reaction between carboxylic acid and borane at room temperature, dose of the catalyst is only 0.8mol% of the mole ratio of carboxylic acid, compared with the conventional catalysis system, the commercial reagent anilino lithium compound is used, reaction conditions are mild, and yield of borate with different substituents under limit conditions can reach 90% or higher.
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(2019/03/06)

Based on n-butyl aromatic carboxylic acid preparation of alcohol compound
The present invention relates to n-butyl application, in particular to based on n-butyl aromatic carboxylic acid preparation of alcohol compound, the catalyst sequentially, borane and carboxylic acid uniformly stirred and mixed, exposed to the air after the reaction terminated in the reaction, the reaction solution under reduced pressure to remove the solvent, then adding silica gel methanol hydrolyzed to obtain the alcohol compound. The invention discloses a butyl lithium can be high activity under the room temperature condition of catalytic carboxylic acid and borane borohydride reaction, the catalyst levels are only the molar amount of carboxylic acid 0.5 μM %, compared with the prior catalytic system, using the commercial reagent is BuLi, mild reaction conditions, in under a limited condition of different substituents of the yield of the ester can reach 90% or more.
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(2019/03/29)

Catalytic Amination of β-(Hetero)arylethyl Ethers by Phosphazene Base t-Bu-P4
We describe the catalytic amination of β-(hetero)arylethyl ethers with amines using the organic superbase t-Bu-P4 to obtain β-(hetero)arylethylamines. The reaction has a broad substrate scope and allows the transformations of electron-deficient and electron-neutral β-(hetero)arylethyl ethers with various amines including pyrrole, N-alkylaniline, diphenylamine, aniline, indole, and indoline derivatives. Mechanistic studies indicate a two-reaction pathway of MeOH elimination from the substrate to form a (hetero)arylalkene followed by the hydroamination of the alkene.
Shigeno, Masanori,Nakamura, Ryutaro,Hayashi, Kazutoshi,Nozawa-Kumada, Kanako,Kondo, Yoshinori
supporting information
p. 6695 - 6699
(2019/09/07)

Interconverting Lanthanum Hydride and Borohydride Catalysts for C=O Reduction and C?O Bond Cleavage
The high catalytic reactivity of homoleptic tris(alkyl) lanthanum La{C(SiHMe2)3}3 is highlighted by C?O bond cleavage in the hydroboration of esters and epoxides at room temperature. The catalytic hydroboration tolerates functionality typically susceptible to insertion, reduction, or cleavage reactions. Turnover numbers (TON) up to 10 000 are observed for aliphatic esters. Lanthanum hydrides, generated by reactions with pinacolborane, are competent for reduction of ketones but are inert toward esters. Instead, catalytic reduction of esters requires activation of the lanthanum hydride by pinacolborane.
Patnaik, Smita,Sadow, Aaron D.
supporting information
p. 2505 - 2509
(2019/02/01)

Selective ligand-free cobalt-catalysed reduction of esters to aldehydes or alcohols
Cobalt(ii) salts combined with NaBHEt3 and eventually a base catalyse efficiently and selectively the reduction of esters to aldehydes or alcohols through hydrosilylation by using phenylsilane. Catalyst characterisation by XRD, XPS, TEM and STEM analyses indicates the materials were partially crystalline with the presence of cobalt nanoparticles. Control experiments suggested low valent Co(0) was the active catalytic species involved.
Rysak, Vincent,Descamps-Mandine, Armel,Simon, Pardis,Blanchard, Florent,Burylo, Laurence,Trentesaux, Martine,Vandewalle, Maxence,Collière, Vincent,Agbossou-Niedercorn, Francine,Michon, Christophe
p. 3504 - 3512
(2018/07/29)

Selective Hydrogenation of Aldehydes Using a Well-Defined Fe(II) PNP Pincer Complex in Biphasic Medium
A biphasic process for the hydrogenation of aldehydes was developed using a well-defined iron (II) PNP pincer complex as model system to investigate the performance of various ionic liquids. A number of suitable hydrophobic ionic liquids based on the N(Tf)2? anion were identified, allowing to immobilize the iron (II) catalyst in the ionic liquid layer and to facilitate the separation of the desired alcohols. Further studies showed that targeted Br?nsted basic ionic liquids can eliminate the need of an external base to activate the catalyst.
Weber, Stefan,Brünig, Julian,Zeindlhofer, Veronika,Schr?der, Christian,St?ger, Berthold,Limbeck, Andreas,Kirchner, Karl,Bica, Katharina
p. 4386 - 4394
(2018/09/14)

Cobalt-Catalyzed Hydroboration of Alkenes, Aldehydes, and Ketones
An operationally convenient and general method for hydroboration of alkenes, aldehydes, and ketones employing Co(acac)3 as a precatalyst is reported. The hydroboration of alkenes in the presence of HBpin, PPh3, and NaOtBu affords good to excellent yields with high Markovnikov selectivity with up to 97:3 branched/linear selectivity. Moreover, Co(acac)3 could be used effectively to hydroborate aldehydes and ketones in the absence of additives under mild reaction conditions. Inter- and intramolecular chemoselective reduction of the aldehyde group took place over the ketone functional group.
Tamang, Sem Raj,Bedi, Deepika,Shafiei-Haghighi, Sara,Smith, Cecilia R.,Crawford, Christian,Findlater, Michael
p. 6695 - 6700
(2018/11/21)

Visible-Light-Mediated Aerobic Oxidation of Organoboron Compounds Using in Situ Generated Hydrogen Peroxide
A simple and general visible-light-mediated oxidation of organoboron compounds has been developed with rose bengal as the photocatalyst, substoichiometric Et3N as the electron donor, as well as air as the oxidant. This mild and metal-free protocol shows a broad substrate scope and provides a wide range of aliphatic alcohols and phenols in moderate to excellent yields. Notably, the robustness of this method is demonstrated on the stereospecific aerobic oxidation of organoboron compounds.
Weng, Wei-Zhi,Liang, Hao,Zhang, Bo
p. 4979 - 4983
(2018/08/24)

Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
supporting information
p. 14848 - 14859
(2017/10/27)

A Versatile Iridium(III) Metallacycle Catalyst for the Effective Hydrosilylation of Carbonyl and Carboxylic Acid Derivatives
A versatile iridium(III) metallacycle catalysed rapidly and selectively the reduction of a large array of challenging esters and carboxylic acids as well as various ketones and aldehydes. The reactions proceeded in high yields at room temperature by hydrosilylation followed by desilylation. Although the reactions of various aldehydes and ketones resulted exclusively in alcohols, the hydrosilylation of esters led to alcohols or ethers, depending on the type of substrate. Regarding the carboxylic acids, again the nature of the reagent controlled the outcome of the hydrosilylation reaction, either alcohols or aldehydes being formed.
Corre, Yann,Rysak, Vincent,Trivelli, Xavier,Agbossou-Niedercorn, Francine,Michon, Christophe
p. 4820 - 4826
(2017/09/07)

Iron Catalyzed Hydroboration of Aldehydes and Ketones
We report an operationally convenient room temperature hydroboration of aldehydes and ketones employing Fe(acac)3 as precatalyst. The hydroboration of aldehydes and ketones proceeded efficiently at room temperature to yield, after work up, 1° and 2° alcohols; chemoselective hydroboration of aldehydes over ketones is attained under these conditions. We propose a σ-bond metathesis mechanism in which an Fe-H intermediate is postulated to be a key reactive species.
Tamang, Sem Raj,Findlater, Michael
p. 12857 - 12862
(2017/12/08)

Regioselective hydrosilylation of epoxides catalysed by nickel(II) hydrido complexes
Bench-stable nickel fluoride complexes bearing NNN pincer ligands have been employed as precursors for the regioselective hydrosilylation of epoxides at room temperature. A nickel hydride assisted epoxide opening is followed by the cleavage of the newly formed nickel oxygen bond by σ-bond metathesis with a silane.
Wenz, Jan,Wadepohl, Hubert,Gade, Lutz H.
p. 4308 - 4311
(2017/04/21)

Visible-Light-Mediated Anti-Markovnikov Hydration of Olefins
Considering that stoichiometric borane and oxidant are required in the classical alkene anti-Markovnikov hydration process, it remains appealing to achieve the transformation in a catalytic protocol. Herein, a visible-light-mediated anti-Markovnikov addition of water to alkenes by using an organic photoredox catalyst in conjunction with a redox-active hydrogen atom donor was developed, which avoided the need for a transition-metal catalyst, stoichiometric borane, as well as oxidant. Both terminal and internal olefins are readily accommodated in this transformation to obtain corresponding primary and secondary alcohols in good yields with single regioselectivity. This procedure can be scaled up to gram scale with a 230 turnover number based on photocatalyst.
Hu, Xia,Zhang, Guoting,Bu, Faxiang,Lei, Aiwen
p. 1432 - 1437
(2017/08/09)

Selective One-Pot Three-Step Cascade Reaction: From Aromatic Aldehydes to 2,2-Diphenylethanol Derivatives
We report herein a green and scalable one-pot, three-step, pinacol-coupling-rearrangement-reduction cascade reaction useful for the formation of 2,2-diphenylethanol derivatives. The reaction is carried out in water in the presence of a commercially available and regenerable supported acid under moderate pressure. A dozen of aromatic aldehydes have been successfully submitted to the standard protocol giving the target 2,2-diarylethanol derivatives in good yield (70-85%).
Billamboz, Muriel,Imbs, Claire,Banaszak-Léonard, Estelle,Len, Christophe
supporting information
p. 835 - 843
(2017/06/23)

Ruthenium-Catalyzed Deaminative Hydrogenation of Aliphatic and Aromatic Nitriles to Primary Alcohols
The deaminative hydrogenation of nitriles towards alcohols is a useful reaction to transform nitriles into alcohols with NH3 as the sole byproduct. Using the simple and robust RuHCl(CO)(PPh3)3 complex as a catalyst, at low H2 pressures a series of aliphatic and aromatic nitriles could be transformed into the corresponding alcohols. Suitable solvent systems for these reactions were 1,4-dioxane/water and EtOH/water mixtures. In most cases, the selectivity for the alcohols was excellent, and the corresponding amines were formed only in trace amounts.
Molnár, István Gábor,Calleja, Pilar,Ernst, Martin,Hashmi, A. Stephen K.,Schaub, Thomas
p. 4175 - 4178
(2017/10/09)

Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
NHC-rhodium complexes (NHC=N-heterocyclic carbenes) have been widely used as efficient catalysts for hydrosilylation reactions. However, the substrates were mostly limited to reactive carbonyl compounds (aldehydes and ketones) or carbon-carbon multiple bonds. Here, we describe the application of newly-developed chelating bis(tzNHC)-rhodium complexes (tz=1,2,3-triazol-5-ylidene) for several reductive transformations. With these catalysts, the formal reductive methylation of amines using carbon dioxide, the hydrosilylation of amides and carboxylic acids, and the reductive alkylation of amines using carboxylic acids have been achieved under mild reaction conditions.
Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi, Shu
supporting information
p. 452 - 458
(2016/02/12)

Unsupported Nanoporous Gold Catalyst for Chemoselective Hydrogenation Reactions under Low Pressure: Effect of Residual Silver on the Reaction
For the first time, H-H dissociation on an unsupported nanoporous gold (AuNPore) surface is reported for chemoselective hydrogenation of C=C, C=C, C=N, and C=O bonds under mild conditions (8 atm H2 pressure, 90 °C). Silver doping in AuNPore, which was inevitable for its preparation through a process of dealloying of Au-Ag alloy, exhibited a remarkable difference in catalytic activity between two catalysts, Au>99Ag1NPore and Au90Ag10NPore.The former was more active and the latter less active in H2 hydrogenation, while the reverse tendency was observed for O2 oxidation. This marked contrast between H2 reduction and O2 oxidation is discussed. Further, Au>99Ag1NPore showed a high chemoselectivity toward reduction of terminal alkynes in the presence of internal alkynes which was not achieved using supported gold nanoparticle catalysts and other previously known methods. Reductive amination, which has great significance in synthesis of amines due to its atom-economical nature, was also realized using Au>99Ag1NPore, and the Au>99Ag1NPore/H2 system showed a preference for the reduction of aldehydes in the presence of imines. In addition to this high chemoselectivity, easy recovery and high reusability of AuNPore make it a promising heterogeneous catalyst for hydrogenation reactions.
Takale, Balaram S.,Feng, Xiujuan,Lu, Ye,Bao, Ming,Jin, Tienan,Minato, Taketoshi,Yamamoto, Yoshinori
supporting information
p. 10356 - 10364
(2016/08/31)

METHOD FOR MANUFACTURING ALCOHOL BY HYDROGENATION OF CARBOXYLIC ACID COMPOUND AND ESTER COMPOUND
PROBLEM TO BE SOLVED: To provide a method for obtaining alcohol by hydrogenation of carboxylic acid compound efficiently by using a homogeneous system catalyst, especially a method for obtaining alcohol by hydrogenation of various carboxylic acid compound and ester compound by the homogeneous system catalyst efficiently even under alleviation condition. SOLUTION: A carboxylic acid compound and/or an ester compound is hydrogenated in a presence of a rhenium complex represented by ReXmYnZp, where X is a halogen atom, Y is same or different and each a ligand containing one or more phosphorus atom, Z is a ligand other than X and Y, m is an integer of 1 to 6, p is an integer of 0 to 2 and the sum of m, n and p is an integer of 2 to 6, and a specific alkali metal salt. COPYRIGHT: (C)2015,JPOandINPIT
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(2016/10/10)

METHOD AND APPARATUS FOR THE SYNTHESIS OF DIHYDROARTEMISININ AND ARTEMISININ DERIVATIVES
The present invention is directed to a method for continuous production of dihydroartemisinin and also artemisinin derivatives derived from dihydroartemisinin by using artemisinin or dihydroartemisinic acid (DHAA) as starting material as well as to a continuous flow reactor for producing dihydroartemisinin as well as the artemisinin derivatives. It was found that the reduction of artemisinin to dihydroartemisinin in a continuous process requires a special kind of reactor and a special combination of reagents comprising a hydride reducing agent, at least one activator such as an inorganic activator, at least one solid base, at least one aprotic solvent and at least one C1-C5 alcohol.
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(2015/02/02)

Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
supporting information
p. 10596 - 10599
(2015/09/02)

Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes
A series of ketones and aldehydes are reduced in toluene under H2 in the presence of 5 mol % B(C6F5)3 and either cyclodextrin or molecular sieves affording a facile metal-free protocol for reduction to alcohols. Similar treatment of aryl ketones resulted in metal-free deoxygenation yielding aromatic hydrocarbons.
Mahdi, Tayseer,Stephan, Douglas W.
supporting information
p. 8511 - 8514
(2015/11/27)

Iron-Catalyzed Hydrosilylation of Aldehydes and Ketones under Solvent-Free Conditions
Exposure of aldehyde or ketone to 1 mol % BIAN-Fe(C7H8) complex in the presence of diphenyl silane affords the corresponding protected alcohol in excellent yields, under mild reaction conditions. Aldehydes and ketones are reduced cleanly in the presence of a broad range of functional groups under solvent-free conditions.
Wekesa, Francis S.,Arias-Ugarte, Renzo,Kong, Lydia,Sumner, Zachary,McGovern, Gregory P.,Findlater, Michael
p. 5051 - 5056
(2015/11/09)

Development of a flow method for the hydroboration/oxidation of olefins
A method for the continuous preparation of alcohols by hydroboration/oxidation of olefins using flow techniques is described. The process allows the isolation of up to 120 mmol h-1 of the desired alcohol in a very rapid manner with good functional group tolerance. The flow setup can be modified to perform a continuous extraction of the desired alcohol from the biphasic mixture produced by the reaction. This journal is
Souto, José A.,Stockman, Robert A.,Ley, Steven V.
p. 3871 - 3877
(2015/03/30)

1,4-dihydropyridine-3,5-dicarboxylate Derivatives And Preparation And Use Thereof
The present invention relates to a 1,4-dihydropyridine-3,5-dicarboxylate compound of general compound (I), a process for preparing the same, a use thereof for the manufacture of a medicament for treating and/or preventing kidney injury, cardiovascular diseases and/or endocrine diseases, as well as a pharmaceutical composition and a pharmaceutical formulation containing said compounds, wherein the definitions of R1, R2, R3, R4, R5, R6, R7, R8, m, n1, n2, p and q are the same as those defined in the description.
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Paragraph 0161; 0162

(2014/03/21)

1,4-DIHYDROPYRIDINE -3,5-DICARBOXYLATE DERIVATIVES, PREPARATION METHODS AND USES THEREOF
The present invention relates to a 1,4-dihydropyridine-3,5-dicarboxylate compound of general compound (I), a process for preparing the same, a use thereof for the manufacture of a medicament for treating and/or preventing kidney injury, cardiovascular diseases and/or endocrine diseases, as well as a pharmaceutical composition and a pharmaceutical formulation containing said compounds, wherein the definitions of R1, R2, R3, R4, R5, R6, R7, R8, m, n1, n2, p and q are the same as those defined in the description.
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Paragraph 0145; 0146

(2014/03/25)

Nickel-catalyzed regiodivergent opening of epoxides with aryl halides: Co-catalysis controls regioselectivity
Epoxides are versatile intermediates in organic synthesis, but have rarely been employed in cross-coupling reactions. We report that bipyridine-ligated nickel can mediate the addition of functionalized aryl halides, a vinyl halide, and a vinyl triflate to epoxides under reducing conditions. For terminal epoxides, the regioselectivity of the reaction depends upon the cocatalyst employed. Iodide cocatalysis results in opening at the less hindered position via an iodohydrin intermediate. Titanocene cocatalysis results in opening at the more hindered position, presumably via TiIII-mediated radical generation. 1,2-Disubstituted epoxides are opened under both conditions to form predominantly the trans product.
Zhao, Yang,Weix, Daniel J.
supporting information
p. 48 - 51
(2014/01/23)

A molecularly defined iron-catalyst for the selective hydrogenation of α,β-unsaturated aldehydes
A selective iron-based catalyst system for the hydrogenation of α,β-unsaturated aldehydes to allylic alcohols is presented. Applying the defined iron-tetraphos complex [FeF(L)][BF4] (L=P(PhPPh 2)3) in the presence of trifluoroacetic acid a broad range of aldehydes are reduced in high yields using low catalyst loadings (0.05-1 mol %). Excellent chemoselectivity for the reduction of aldehydes in the presence of other reducible moieties, for example, ketones, olefins, esters, etc. is achieved. Based on the in situ detected hydride species [FeH(H 2)(L)]+ a catalytic cycle is proposed that is supported by computational calculations. Copyright
Wienh?fer, Gerrit,Westerhaus, Felix A.,Junge, Kathrin,Ludwig, Ralf,Beller, Matthias
supporting information
p. 7701 - 7707
(2013/07/11)

Reductions of aldehydes and ketones with a readily available N-heterocyclic carbene borane and acetic acid
Acetic acid promotes the reduction of aldehydes and ketones by the readily available N-heterocyclic carbene borane, 1,3-dimethylimidazol-2-ylidene borane. Aldehydes are reduced over 1-24 h at room temperature with 1 equiv of acetic acid and 0.5 equiv of the NHC-borane. Ketone reductions are slower but can be accelerated by using 5 equiv of acetic acid. Aldehydes can be selectively reduced in the presence of ketones. On a small scale, products are isolated by evaporation of the reaction mixture and direct chromatography.
Lamm, Vladimir,Pan, Xiangcheng,Taniguchi, Tsuyoshi,Curran, Dennis P.
p. 675 - 680
(2013/05/21)

Fast and selective iron-catalyzed transfer hydrogenations of aldehydes
An efficient iron-based catalyst system consisting of Fe(BF)4$6H2O and P(CH2CH2PPh2)3 [tetraphos, (PP3)] is presented for the highly selective transfer hydrogenation of aromatic, aliphatic, and a,b-unsaturated aldehydes. A wide range of substrates including aldehydes with other reducible functional groups gave the corresponding alcohols in good yields. Formic acid is applied as a cheap, environmentally benign and easy to handle hydrogen source. Notable features of the presented methodology are the fast reactions under mild conditions. Advantageously compared to most transfer hydrogenations, no stoichiometric amounts of base additives are required.
Wienh?fer, Gerrit,Westerhaus, Felix A.,Junge, Kathrin,Beller, Matthias
p. 156 - 159
(2013/10/01)

Copper(II) triflate-catalyzed reduction of carboxylic acids to alcohols and reductive etherification of carbonyl compounds
A protocol is described for the reduction of carboxylic acids to primary alcohols using 1,1,3,3-tetramethyldisiloxane (TMDS) and a catalytic amount of Cu(OTf)2. Aliphatic as well as aromatic carboxylic acids are reduced in high selectivity and good yields. TMDS/Cu(OTf)2 has also been found to be an efficient catalytic reducing system for the preparation of symmetrical ethers from carbonyl compounds under mild conditions.
Zhang, Yin-Jie,Dayoub, Wissam,Chen, Guo-Rong,Lemaire, Marc
experimental part
p. 7400 - 7407
(2012/09/10)

Silica gel promotes reductions of aldehydes and ketones by N-heterocyclic carbene boranes
N-Heterocyclic carbene boranes (NHC-boranes) such as 1,3-dimethylimidazol- 2-ylidine trihydridoborane (diMe-Imd-BH3) serve as practical hydride donors for the reduction of aldehydes and ketones in the presence of silica gel. Primary and secondary alcohols are formed in good yields under ambient conditions. Aldehydes are selectively reduced in the presence of ketones. One, two, or even all three of the boron hydrides can be transferred. The process is attractive because all the components are stable and easy to handle and because both the reaction and isolation procedures are convenient.
Taniguchi, Tsuyoshi,Curran, Dennis P.
p. 4540 - 4543
(2012/10/29)

Substrate range of the titanium TADDOLate catalyzed asymmetric fluorination of activated carbonyl compounds
The substrate range of the [TiCl2(TADDOLate)] (TADDOL=α,α,α′,α′-tetraaryl-1,3-dioxolane-4, 5-dimethanol)-catalyzed asymmetric α-fluorination of activated β-carbonyl compounds has been investigated. Optimal conditions for catalysis are characterized by using 5 mol-% of TiCl2(naphthalen-1- yl)-TADDOLate) as catalyst in a saturated (0.14 mol/l) MeCN solution of F-TEDA (1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis- [tetrafluoroborate]) at room temperature. A series of α-methylated β-keto esters (3-oxobutanoates, 3-oxopentanoates) with bulky benzyl ester groups (60-90% ee) or phenyl ester (67-88% ee) have been fluorinated readily, whereas α-acyl lactones were also readily fluorinated, but gave lower inductions (13-46% ee). Double stereochemical differentiation in β-keto esters with chiral ester groups raised the stereoselectivity to a diastereomeric ratio (dr) of up to 96.5:3.5. For the first time, β-keto S-thioesters were asymmetrically fluorinated (62-91.5% ee) and chlorinated (83% ee). Lower inductions were observed in fluorinations of 1,3-diketones (up to 40% ee) and β-keto amides (up to 59% ee). General strategies for preparing activated β-carbonyl compounds as important model substrates for asymmetric catalytic α-functionalizations are presented (>60 examples). Copyright
Bertogg, Andreas,Hintermann, Lukas,Huber, Dominique P.,Perseghini, Mauro,Sanna, Maria,Togni, Antonio
body text
p. 353 - 403
(2012/05/07)

Calcium-mediated hydroboration of alkenes: "trojan horse" or "true" catalysis?
The hydroboration of 1,1-diphenylethylene (DPE) with catecholborane (HBcat) proceeds at 100 °C. For conversion at room temperature three different organocalcium catalysts have been investigated: the calcium hydride complex [DIPPnacnacCaH·(THF)]2 (1, DIPPnacnac = CH{(CMe)(2,6-iPr 2C6H3N)}2), Ca[2-Me 2N-α-Me3Si-benzyl)2·(THF) 2 (2) and DIPPnacnacCa(H-BBN)·(THF) (3, BBN = 9-borabicyclo[3.3.1.]nonane). Although up to 96% conversion of DPE is found, the product of the reaction is not the expected Ph2CHCH2Bcat but (Ph2CHCH2)3B is formed instead. Organocalcium compounds catalyze the decomposition of HBcat to B 2(cat)3 and BH3 (or B2H6) and the latter is involved in hydroboration of DPE. The calcium-catalyzed decomposition of HBcat was investigated with 11B NMR and the signals were assigned to the following species: B2(cat)3, B(cat)2-, HBcat, BH3(THF), BH4 - and B2H7-. A tentative mechanism for the formation of these species was proposed. The intermediate DIPPnacnacCa(BH4)·(THF)2 (5) was independently prepared by reaction of 1 and BH3(Me2S) and was structurally characterized by X-ray diffraction. Stoichiometric reaction of 1 with pinacolborane (HBpin) gave a trimeric complex [DIPPnacnacCa(H 2Bpin)]3 (6) which was structurally characterized by X-ray diffraction. This complex does not react with DPE, also not at elevated temperatures. The possible equilibrium between 6 and 1/HBpin is therefore fully at the side of 6. As 6 is unstable in the presence of HBpin, no further catalytic conversions have been investigated.
Harder, Sjoerd,Spielmann, Jan
body text
p. 7 - 14
(2012/02/04)

Metal-free catalytic reduction of aldehydes, ketones, aldimines, and ketimines
The metal-free combination of catalytic amounts of PPh3, B(C6F5)3, and PhSiH3 can efficiently hydrosilylate aldehydes, ketones, aldimines and ketimines to afford the corresponding reduction products in good yields.
Matsuoka, Hiroaki,Kondo, Kazuhiro
scheme or table
p. 1314 - 1317
(2011/10/08)

Zinc(II) iodide-triethylsilane: A novel mild reduction system for direct deoxygenation of aryl aldehydes, ketones, and α,β-unsaturated enones
ZnI2-TESH has been found to be a novel mild and efficient reduction system. This reagent, in contrast to the traditional ionic deoxygenation systems (TFA-R3SiH, BF3·OEt 2-R3SiH, etc.), could directly deoxygenate different kinds of carbonyl compounds such as aryl aldehydes, ketones, and αβ- unsaturated enones to the corresponding hydrocarbons in moderate to excellent yields. Georg Thieme Verlag Stuttgart.
Li, Zheng,Deng, Gang,Li, Yuan-Chao
experimental part
p. 3053 - 3057
(2009/07/03)

Proline-catalyzed highly enantioselective and anti-selective mannich reaction of unactivated ketones: Synthesis of chiral α-amino acids
(Chemical Equation Presented) Universal L-proline: The title reaction complements well-known syn-selective Mannich reactions. The Mannich products can be converted readily into the free amino acids by hydrogenolytic deprotection under mild conditions (see scheme). DMSO = dimethyl sulfoxide; R1 = alkyl, OH; R2 = alkyl.
Hahn, Bjoern T.,Froehlich, Roland,Harms, Klaus,Glorius, Frank
supporting information; experimental part
p. 9985 - 9988
(2009/04/21)

New 1,3-dioxolane and 1,3-dioxane derivatives as effective modulators to overcome multidrug resistance
Multidrug resistance (MDR) to antitumor agents represents a major obstacle to a successful chemotherapy of cancer. Overexpression of P-glycoprotein (p-gp) seems to be the major factor responsible for MDR. A large number of chemically unrelated compounds are known to interact with p-gp resulting in a decreasing resistance. In our efforts related to structure-activity studies of new potential MDR reversal agents we synthesized a series of compounds that differ in the aromatic core structure, the linker, and the basic moiety. For our search of new aromatic core structures we synthesized novel 2,2-diphenyl-1,3-dioxolane, 2,2- diphenyl-1,3-dioxane, and 4,5-diphenyl-1,3-dioxolane derivatives. A range of lipophilic linker structures and protonable basic moieties were synthesized and investigated to optimize the structure of the potential MDR-modulators. The compounds were tested in vitro using human Caco-2 cells. Both the cytotoxicity of the synthons and their ability to resensitize the cells were determined with a MTT assay. The results show that at low concentration various substances reverse tumor cell MDR. Some of the new structures show better effects than established modulators like trifluoperazine.
Schmidt, Matthias,Ungvari, Johannes,Gloede, Julia,Dobner, Bodo,Langner, Andreas
p. 2283 - 2297
(2007/10/03)

Synthesis and biological studies of novel 2-aminoalkylethers as potential antiarrhythmic agents for the conversion of atrial fibrillation
A series of 2-aminoalkylethers prepared as potential antiarrhythmic agents is described. The present compounds are mixed sodium and potassium ion channel blockers and exhibit antiarrhythmic activity in a rat model of ischemia-induced arrhythmias. Structure-activity studies led to the identification of three compounds 5, 18, and 26, which were selected based on their particular in vivo electrophysiological properties, for studies in two canine atrial fibrillation (AF) models. The three compounds converted AF in both models, but only compound 26 was shown to be orally bioavailable. Resolution of the racemate 26 into its corresponding enantiomers 40 and 41 and subsequent biological testing of these enantiomers led to the selection of (1S,2S)-1-(1-naphthalenethoxy)-2-(3- ketopyrrolidinyl)cyclohexane monohydrochloride (41) as a potential atrial selective antiarrhythmic candidate for further development.
Plouvier, Bertrand,Beatch, Gregory N.,Jung, Grace L.,Zolotoy, Alexander,Sheng, Tao,Clohs, Lilian,Barrett, Terrance D.,Fedida, David,Wang, Wei Q.,Zhu, Jeff J.,Liu, Yuzhong,Abraham, Shlomo,Lynn, Leah,Dong, Ying,Wall, Richard A.,Walker, Michael J. A.
p. 2818 - 2841
(2008/02/09)