101219-69-6Relevant articles and documents
Efficient and Practical Transfer Hydrogenation of Ketones Catalyzed by a Simple Bidentate Mn?NHC Complex
van Putten, Robbert,Benschop, Joeri,de Munck, Vincent J.,Weber, Manuela,Müller, Christian,Filonenko, Georgy A.,Pidko, Evgeny A.
, p. 5232 - 5235 (2019)
Catalytic reductions of carbonyl-containing compounds are highly important for the safe, sustainable, and economical production of alcohols. Herein, we report on the efficient transfer hydrogenation of ketones catalyzed by a highly potent Mn(I)?NHC complex. Mn?NHC 1 is practical at metal concentrations as low as 75 ppm, thus approaching loadings more conventionally reserved for noble metal based systems. With these low Mn concentrations, catalyst deactivation is found to be highly temperature dependent and becomes especially prominent at increased reaction temperature. Ultimately, understanding of deactivation pathways could help close the activity/stability-gap with Ru and Ir catalysts towards the practical implementation of sustainable earth-abundant Mn-complexes.
Asymmetric transfer hydrogenation of ketones catalyzed by rhenium complexes with chiral ferrocenylphosphane ligands
Mejia, Esteban,Aardoom, Raphael,Togni, Antonio
, p. 5021 - 5032,12 (2012)
We have prepared a series of new rhenium complexes containing chiral ferrocenyldiphosphane ligands of the Josiphos family, starting from commercially available rhenium sources. These new ReV oxido and nitrido complexes, several of which have been characterized by X-ray crystallography, are air- and moisture-stable and are active catalysts in the asymmetric transfer hydrogenation of ketones using 2-propanol as the hydrogen source in the presence of substoichiometric amounts of triethylamine (TEA). The reaction proceeds cleanly with good to excellent yields (50-99 %) but with moderate enantioselectivity (up to 58 % ee). A mechanism not involving hydridic species is proposed.
Highly Active and Selective Manganese C=O Bond Hydrogenation Catalysts: The Importance of the Multidentate Ligand, the Ancillary Ligands, and the Oxidation State
Kallmeier, Fabian,Irrgang, Torsten,Dietel, Thomas,Kempe, Rhett
, p. 11806 - 11809 (2016)
The replacement of expensive noble metals by earth-abundant transition metals is a central topic in catalysis. Herein, we introduce a highly active and selective homogeneous manganese-based C=O bond hydrogenation catalyst. Our catalyst has a broad substrate scope, it is able to hydrogenate aryl–alkyl, diaryl, dialkyl, and cycloalkyl ketones as well as aldehydes. A very good functional group tolerance including the quantitative and selective hydrogenation of a ketone in the presence of a non-shielded olefin is observed. In Mn hydrogenation catalysis, the combination of the multidentate ligand, the oxidation state of the metal, and the choice of the right ancillary ligand is crucial for high activity. This observation emphasizes an advantage and the importance of homogeneous catalysts in 3d-metal catalysis. For coordination compounds, fine-tuning of a complex coordination environment is easily accomplished in comparison to enzyme and/or heterogeneous catalysts.
Chiral Imidazo[1,5- a]pyridine-Oxazolines: A Versatile Family of NHC Ligands for the Highly Enantioselective Hydrosilylation of Ketones
Chinna Ayya Swamy,Varenikov, Andrii,Ruiter, Graham De
, p. 247 - 257 (2020)
Herein we report the synthesis and application of a versatile class of N-heterocyclic carbene ligands based on an imidazo[1,5-a]pyridine-3-ylidine backbone that is fused to a chiral oxazoline auxiliary. The key step in the synthesis of these ligands involves the installation of the oxazoline functionality via a microwave-assisted condensation of a cyano-azolium salt with a wide variety of 2-amino alcohols. The resulting chiral bidentate NHC-oxazoline ligands form stable complexes with rhodium(I) that are efficient catalysts for the enantioselective hydrosilylation of structurally diverse ketones. The corresponding secondary alcohols are isolated in good yields (typically >90%) with good to excellent enantioselectivities (80-93% ee). The reported hydrosilylation occurs at ambient temperatures (40 °C), with excellent functional group tolerability. Even ketones bearing heterocyclic substituents (e.g., pyridine or thiophene) or complex organic architectures are hydrosilylated efficiently, which is discussed further in this report.
Neutral Dinuclear Copper(I)-NHC Complexes: Synthesis and Application in the Hydrosilylation of Ketones
Trose, Michael,Lazreg, Fa?ma,Chang, Tao,Nahra, Fady,Cordes, David B.,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.
, p. 238 - 242 (2017)
The synthesis of a class of highly stable neutral dinuclear Cu(I)-NHC complexes using 1,2,4-triazole as a bridging ligand is described. Various NHCs were used to generate a library of [Cu(μ-trz)(NHC)]2 complexes. Interestingly, [Cu(μ-trz)(IPr)]2 was found to be highly active in the hydrosilylation of ketones, without the need for an external base or any other additive. A wide range of aryl and alkyl ketones, as well as sterically hindered ketones, was successfully reduced to alcohols using the lowest catalyst loading reported to date.
Reduction of ketones with silanes catalysed by a cyclopentadienyl- functionalised N-heterocyclic iron complex
Lopes, Rita,Cardoso, Joao M.S.,Postigo, Lorena,Royo, Beatriz
, p. 1061 - 1066 (2013)
The well-defined piano-stool iron(II) complex (Cp-NHC)Fe(CO)I bearing a bidentate cyclopentadienyl-functionalised N-heterocyclic carbene ligand is shown to catalyse the reduction of ketones under mild conditions (1-2 h at room temperature) when combined with catalytic amounts of potassium tert-butoxide, and using Ph2SiH2 and the inexpensive and less reactive polymethylhydrosiloxane as reducing agents. The stoichiometric reaction of (Cp-NHC)Fe(CO)I with potassium tert-butoxide generates an iron-hydroxo complex, which seems to be the active species in the reduction of ketones.
Constructing reactive Fe and Co complexes from isolated picolyl-functionalized N-heterocyclic carbenes
Liang, Qiuming,Liu, Nina Jiabao,Song, Datong
, p. 9889 - 9896 (2018)
We report the isolation of free picolyl-functionalized N-heterocyclic carbenes (NHCs), which serve as versatile precursors to access low coordinate iron and cobalt complexes. The reactivities of these new iron and cobalt complexes towards catalytic hydrosilylation of ketones have also been explored. For example, low loadings (0.05-1 mol%) of a four-coordinate iron complex bearing two deprotonated picolyl-NHC ligands can effect the fast catalytic reduction of ketones using the inexpensive industrial byproduct polymethylhydrosiloxane (PMHS) as the reductant at ambient temperature.
Hydrogenation of Carbonyl Derivatives Catalysed by Manganese Complexes Bearing Bidentate Pyridinyl-Phosphine Ligands
Wei, Duo,Bruneau-Voisine, Antoine,Chauvin, Téo,Dorcet, Vincent,Roisnel, Thierry,Valyaev, Dmitry A.,Lugan, No?l,Sortais, Jean-Baptiste
, p. 676 - 681 (2018)
Manganese(I) catalysts incorporating readily available bidentate 2-aminopyridinyl-phosphine ligands achieve a high efficiency in the hydrogenation of carbonyl compounds, significantly better than parent ones based on more elaborated and expensive tridentate 2,6-(diaminopyridinyl)-diphosphine ligands. The reaction proceeds with low catalyst loading (0.5 mol%) under mild conditions (50 °C) with yields up to 96%. (Figure presented.).
Commutative reduction of aromatic ketones to arylmethylenes/alcohols by hypophosphites catalyzed by Pd/C under biphasic conditions
Guyon, Carole,Baron, Marc,Lemaire, Marc,Popowycz, Florence,Métay, Estelle
, p. 2088 - 2095 (2014)
An efficient method is reported to reduce aromatic ketones selectively into arylmethylenes or alcohols with hypophosphites and Pd/C, depending on the selected conditions. This study could represent a promising alternative to the classical uses of standard hydrides or molecular hydrogen involved in reduction and deoxygenation procedures.
Hydrogenation of ketones with a manganese PN3P pincer pre-catalyst
Bruneau-Voisine, Antoine,Wang, Ding,Roisnel, Thierry,Darcel, Christophe,Sortais, Jean-Baptiste
, p. 1 - 4 (2017)
A catalytic hydrogenation of carbonyl derivatives with a manganese pre-catalyst has been developed. The key feature is the use of an air stable cationic manganese pre-catalyst bearing a tridendate ligand with a 2,6-(diaminopyridinyl)diphosphine scaffold. Under 50?bar of H2, at 130?°C, various ketones were reduced to the corresponding alcohols with moderate to good yield.
Heterogenized Wilkinson-type catalyst for transfer hydrogenation of carbonyl compounds
Bogar, Krisztian,Krumlinde, Patrik,Bacsik, Zoltan,Hedin, Niklas,Baeckvall, Jan-E.
, p. 4409 - 4414 (2011)
Wilkinson's catalyst [RhCl(PPh3)3] was heterogenized on common silica by the use of a grafting/anchoring technique. The immobilized catalyst showed high activity and selectivity in transfer hydrogenation reactions of a range of carbonyl compounds in 2-propanol. Reactions carried out in 2-propanol at reflux afforded the corresponding alcohols in high yields in short reaction times. The heterogeneous feature of the catalyst allows for easy recovery and efficient reuse in the same reaction up to 5 times without any detectible loss of catalytic activity. Wilkinson's catalyst [RhCl(PPh 3)3] has been immobilized on silica through a monodentate phosphane ligand and used in the transfer hydrogenation of alkyl and aryl carbonyl compounds. The use of 2-propanol as both hydrogen donor and solvent allows for high yields of the corresponding alcohols under mild reaction conditions. The recyclability of this heterogenized Rh catalyst is also demonstrated.
Core-shell structured mesoporous silica: A new immobilized strategy for rhodium catalyzed asymmetric transfer hydrogenation
Zhang, Huaisheng,Jin, Ronghua,Yao, Hui,Tang, Shuang,Zhuang, Jinglan,Liu, Guohua,Li, Hexing
, p. 7874 - 7876 (2012)
A core-shell structured heterogeneous rhodium catalyst exhibited excellent catalytic activity and enantioselectivity in asymmetric transfer hydrogenation of aromatic ketones in aqueous medium, which could be recovered easily and used repetitively twelve times without affecting obviously its enantioselectivity.
A simple and efficient catalytic method for the reduction of ketones
Ekstroem, Jesper,Wettergren, Jenny,Adolfsson, Hans
, p. 1609 - 1613 (2007)
A range of ketones was efficiently reduced in the presence of catalytic amounts of lithium isopropoxide in 2-propanol under microwave heating, with alcohol products being formed in yields up to 99%.
Asymmetric transfer hydrogenation of ketones promoted by manganese(I) pre-catalysts supported by bidentate aminophosphines
Azouzi, Karim,Bruneau-Voisine, Antoine,Vendier, Laure,Sortais, Jean-Baptiste,Bastin, Stéphanie
, (2020)
A series of commercially available chiral amino-phosphines, in combination with Mn(CO)5Br, has been evaluated for the asymmetric reduction of ketones, using isopropanol as hydrogen source. With the most selective ligand, the corresponding manga
Synthesis, structural characterization and catalytic transfer hydrogenation of ruthenium(II) carbonyl complexes bearing N,N,O pincer type benzoylhydrazone ligands
Suganthy, Pandimuni Kalpaga,Prabhu, Rupesh Narayana,Sridevi, Venugopal Shanmugham
, p. 57 - 62 (2015)
The convenient synthesis of four new octahedral ruthenium(II) carbonyl benzoylhydrazone complexes of the general molecular formula [Ru(L)Cl(CO)(PPh3)] (where HL = substituted 2-acetylpyridine benzoylhydrazones; the H represents the dissociable
Copper-catalyzed asymmetric hydrosilylation of ketones using air and moisture stable precatalyst Cu(OAc)2·H2O
Lee, Dong-Won,Yun, Jaesook
, p. 5415 - 5417 (2004)
Air and moisture stable copper(II) salts can be used to catalyze the hydrosilylation of aromatic ketones. The combination of catalytic amounts of copper(II) acetate or copper(II) acetate monohydrate (Cu(OAc) 2·H2O) and BINAP in the p
Chemoselective reduction of aldehydes and ketones by potassium diisobutyl-t-butoxy aluminum hydride (PDBBA)
Kim, Joo Yeon,Shin, Won Kyu,Jaladi, Ashok Kumar,An, Duk Keun
, p. 4236 - 4241 (2018)
t-Butoxy derivatives of DIBALH [lithium diisobutyl-t-butoxyaluminum hydride (LDBBA), sodium diisobutyl-t-butoxyaluminum hydride (SDBBA), and potassium diisobutyl-t-butoxyaluminum hydride (PDBBA)] were examined as chemoselective reducing agents of carbonyl compounds. Among them, PDBBA was found to be the most efficient for the reduction of aldehydes and ketones to the corresponding alcohols in the presence of ester, amide, and nitrile substituents at ambient temperature. In addition, the optimal conditions gave higher chemoselectivity for aldehydes in the presence of ketones.
Cyclopentadienyliron dicarbonyl dimer: A simple tool for the hydrosilylation of aldehydes and ketones under air
Jung, Thais Cordeiro,Argouarch, Gilles,Van De Weghe, Pierre
, p. 52 - 54 (2016)
The readily available iron complex [CpFe(CO)2]2 (1) exhibits good catalytic activity in the hydrosilylation of aldehydes and ketones in the presence of diethoxymethylsilane. The procedure described is air-tolerant and applicable to a wide range of substrates.
FUNGAL HYDROXYLATION OF ETHYL BENZENE AND DERIVATIVES
Holland, Herbert L.,Carter, Ian M.,Chenchaiah, P. Chinna,Khan, Shaheer H.,Munoz, Benito,et al.
, p. 6409 - 6412 (1985)
The fungus Mortierella isabellina converts ethyl benzene and a number of para-substituted derivatives to the corresponding optically active 1-phenylethanols with enantiomeric excesses between 5 and 40percent.Hydrogen removal from the substrate preceeds product formation and is stereochemically independent of it.
Reduction of carbonyl compounds via hydrosilylation catalyzed by well-defined PNP-Mn(I) hydride complexes
Weber, Stefan,Iebed, Dina,Glatz, Mathias,Kirchner, Karl
, p. 635 - 639 (2021)
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.]
N-heterocyclic carbene complexes of nickel as efficient catalysts for hydrosilylation of carbonyl derivatives
Postigo, Lorena,Royo, Beatriz
, p. 2613 - 2618 (2012)
Well-defined nickel(II) complexes bearing bidentate tetramethylcyclopentadienyl-functionalised N-heterocyclic carbene ligands (Cp*- NHCMe)NiX (X=Cl, O-t-Bu) have been prepared and applied as efficient catalysts for the hydrosilylation of carbonyl groups. The nickel-alkoxide (Cp*- NHCMe)NiACHTUNGTRENUNG(O-t-Bu) complex displayed remarkable catalytic activity in the reduction of aldehydes, affording quantitative conversion to the corresponding alcohols in 5 min at 25 °C. Mechanistic studies, based on stoichiometric reactions, revealed that the transient nickel hydride (Cp*-NHCMe)NiH complex is the active species in the hydrosilylation of carbonyls.
New efficient organocatalytic oxidation of benzylic compounds by molecular oxygen under mild conditions
Tong, Xinli,Xu, Jie,Miao, Hong,Gao, Jin
, p. 1763 - 1766 (2006)
Efficient aerobic oxidation of benzylic compounds has been achieved under no irradiation using a new organocatalytic system in the presence of acridine yellow and N-hydroxyphthalimide with assistance of a catalytic amount of molecular bromine. Various substrates, especially alkylaromatics, were effectively oxygenated to the corresponding carbonyl compounds with molecular oxygen as oxidant under mild conditions. For instance, indan was oxidized with 92% conversion and 79% selectivity for 1-indanone under 0.3 MPa of O2 at 75°C.
Regiodivergent Reductive Opening of Epoxides by Catalytic Hydrogenation Promoted by a (Cyclopentadienone)iron Complex
Tadiello, Laura,Gandini, Tommaso,Stadler, Bernhard M.,Tin, Sergey,Jiao, Haijun,de Vries, Johannes G.,Pignataro, Luca,Gennari, Cesare
, p. 235 - 246 (2022/01/03)
The reductive opening of epoxides represents an attractive method for the synthesis of alcohols, but its potential application is limited by the use of stoichiometric amounts of metal hydride reducing agents (e.g., LiAlH4). For this reason, the corresponding homogeneous catalytic version with H2 is receiving increasing attention. However, investigation of this alternative has just begun, and several issues are still present, such as the use of noble metals/expensive ligands, high catalytic loading, and poor regioselectivity. Herein, we describe the use of a cheap and easy-To-handle (cyclopentadienone)iron complex (1a), previously developed by some of us, as a precatalyst for the reductive opening of epoxides with H2. While aryl epoxides smoothly reacted to afford linear alcohols, aliphatic epoxides turned out to be particularly challenging, requiring the presence of a Lewis acid cocatalyst. Remarkably, we found that it is possible to steer the regioselectivity with a careful choice of Lewis acid. A series of deuterium labeling and computational studies were run to investigate the reaction mechanism, which seems to involve more than a single pathway.
Highly Active Cooperative Lewis Acid—Ammonium Salt Catalyst for the Enantioselective Hydroboration of Ketones
Titze, Marvin,Heitk?mper, Juliane,Junge, Thorsten,K?stner, Johannes,Peters, René
supporting information, p. 5544 - 5553 (2021/02/05)
Enantiopure secondary alcohols are fundamental high-value synthetic building blocks. One of the most attractive ways to get access to this compound class is the catalytic hydroboration. We describe a new concept for this reaction type that allowed for exceptional catalytic turnover numbers (up to 15 400), which were increased by around 1.5–3 orders of magnitude compared to the most active catalysts previously reported. In our concept an aprotic ammonium halide moiety cooperates with an oxophilic Lewis acid within the same catalyst molecule. Control experiments reveal that both catalytic centers are essential for the observed activity. Kinetic, spectroscopic and computational studies show that the hydride transfer is rate limiting and proceeds via a concerted mechanism, in which hydride at Boron is continuously displaced by iodide, reminiscent to an SN2 reaction. The catalyst, which is accessible in high yields in few steps, was found to be stable during catalysis, readily recyclable and could be reused 10 times still efficiently working.
