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METHOD FOR PRODUCING ALCOHOL
The present invention provides a method for selectively producing an alcohol by efficiently hydrogenating a lactone. The present invention is a method for producing an alcohol, the method including hydrogenating a substrate lactone represented by Formula (1), in the presence of a catalyst described below, to produce an alcohol that is represented by Formula (2). In the formulae, R represents a divalent hydrocarbon group which may have a hydroxyl group. The catalyst comprises: metal species including M1 and M2; and a support supporting the metal species, and wherein M1 is rhodium, platinum, ruthenium, iridium, or palladium; M2 is tin, vanadium, molybdenum, tungsten, or rhenium; and the support is hydroxyapatite, fluorapatite, hydrotalcite, or ZrO2.
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Paragraph 0103-0111; 0124-0127; 0133-0137

(2022/02/05)

Chromium-Catalyzed Production of Diols From Olefins
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111

(2021/03/19)

Chemoselective and Site-Selective Reductions Catalyzed by a Supramolecular Host and a Pyridine-Borane Cofactor
Supramolecular catalysts emulate the mechanism of enzymes to achieve large rate accelerations and precise selectivity under mild and aqueous conditions. While significant strides have been made in the supramolecular host-promoted synthesis of small molecules, applications of this reactivity to chemoselective and site-selective modification of complex biomolecules remain virtually unexplored. We report here a supramolecular system where coencapsulation of pyridine-borane with a variety of molecules including enones, ketones, aldehydes, oximes, hydrazones, and imines effects efficient reductions under basic aqueous conditions. Upon subjecting unprotected lysine to the host-mediated reductive amination conditions, we observed excellent ?-selectivity, indicating that differential guest binding within the same molecule is possible without sacrificing reactivity. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, we then applied this supramolecular reaction to the site-selective labeling of a single lysine residue in an 11-amino acid peptide chain and human insulin.
Morimoto, Mariko,Cao, Wendy,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
supporting information
p. 2108 - 2114
(2021/02/06)

Synthesis and structural elucidation of (pyridyl)imine Fe(II) complexes and their applications as catalysts in transfer hydrogenation of ketones
Reactions of (pyridyl)imine ligands: 2,6-diisopropyl-N-[(pyridine-2-yl)methylene]aniline (L1), 2,6-diisopropyl-N-[(pyridine-2-yl)ethylidene]aniline (L2), 2,6-dimethyl-N-[(pyridine-2-yl)methylene]aniline (L3), 2,6-dimethyl-N-[(pyridine-2-yl)ethylidene]aniline (L4) and N-[(pyridine-2-yl)methylene]aniline (L5) with FeCl2 salt afforded the corresponding paramagnetic Fe(II) complexes [Fe(L1)2Cl][FeCl4] (Fe1), [Fe(L2)2Cl][FeCl4] (Fe2), [Fe(L3)2Cl][FeCl4] (Fe3), [Fe(L4)2Cl][FeCl4], (Fe4), [Fe(L5)2Cl2] (Fe5) in good yields. On the other hand, reactions of L1 with FeCl2 in the presence of NaPF6 afforded complex [Fe(L1)2Cl][PF6] (Fe6) in moderate yields. Molecular structures of complexes Fe1 and Fe2 reveal the formation of cationic species containing two N^N bidentate ligands and one chlorido co-ligand to give five-coordinate geometry with [FeCl4]? as counter-anion. On the other hand, complex Fe5, is an octahedral neutral species containing two bidentate L5 and two chlorido ligands. All the complexes (Fe1–Fe6) formed active catalysts in the transfer hydrogenation of ketones affording average yields of about 85%. The ligand architecture, reaction conditions and nature of substrate influenced the catalytic activities of the complexes. Mercury and subs-stoichiometric poisoning tests pointed to the existence of both Fe(0) nanoparticles and homogeneous Fe(II) species as the active intermediates.
Tsaulwayo, Nokwanda,Kumah, Robert T.,Ojwach, Stephen O.
(2021/01/25)

Ni2P Nanoalloy as an Air-Stable and Versatile Hydrogenation Catalyst in Water: P-Alloying Strategy for Designing Smart Catalysts
Non-noble metal-based hydrogenation catalysts have limited practical applications because they exhibit low activity, require harsh reaction conditions, and are unstable in air. To overcome these limitations, herein we propose the alloying of non-noble metal nanoparticles with phosphorus as a promising strategy for developing smart catalysts that exhibit both excellent activity and air stability. We synthesized a novel nickel phosphide nanoalloy (nano-Ni2P) with coordinatively unsaturated Ni active sites. Unlike conventional air-unstable non-noble metal catalysts, nano-Ni2P retained its metallic nature in air, and exhibited a high activity for the hydrogenation of various substrates with polar functional groups, such as aldehydes, ketones, nitriles, and nitroarenes to the desired products in excellent yields in water. Furthermore, the used nano-Ni2P catalyst was easy to handle in air and could be reused without pretreatment, providing a simple and clean catalyst system for general hydrogenation reactions.
Fujita, Shu,Yamaguchi, Sho,Yamasaki, Jun,Nakajima, Kiyotaka,Yamazoe, Seiji,Mizugaki, Tomoo,Mitsudome, Takato
supporting information
p. 4439 - 4446
(2021/02/09)

Highly efficient catalytic transfer hydrogenation of furfural over defect-rich amphoteric ZrO2with abundant surface acid-base sites
Currently, the catalytic transformation and utilization of biomass-derived compounds are of great importance to the alleviation of environmental problems and sustainable development. Among them, furfural alcohol derived from biomass resources has been found to be one of the most prospective biomass platforms for high-value chemicals and biofuels. Herein, high-surface-area ZrO2 with abundant oxygen defects and surface acid-base sites was synthesized and used as a heterogeneous catalyst for the catalytic transfer hydrogenation of furfural into furfural alcohol using alcohol as a hydrogen donor. The as-synthesized ZrO2 exhibited excellent catalytic performance with 98.2% FA conversion and 97.1% FOL selectivity, even comparable with that of a homogeneous Lewis acid catalyst. A series of characterization studies and experimental results revealed that acid sites on the surface of ZrO2 could adsorb and activate the CO bond in furfural and base sites could facilitate the formation of alkoxide species. The synergistic effect of surface acid-base sites affords a harmonious environment for the reaction, which is crucial for catalytic transfer hydrogenation of furfural with high efficiency. Furthermore, the as-prepared ZrO2 catalyst also exhibited a potential application for the efficient catalytic transfer hydrogenation of a series of biomass-derived carbonyl compounds. This journal is
Zhu, Zekun,Yang, Lingling,Ke, Changxuan,Fan, Guoli,Yang, Lan,Li, Feng
p. 2616 - 2626
(2021/03/03)

Asymmetric reduction of 2-chloro-3-oxo-ester into enantiomerically high pure diltiazem precursor by a Candida ketoreductase
Methyl (2R,3S)-3-(4-methoxyphenyl)glycidate [(2R,3S)-MPGM] is an advanced chiral synthon for the synthesis of the cardiovascular drug diltiazem. It can be easily accessed by cyclizing the reduction products of methyl 2-chloro-3-(4-methoxyphenyl)-3-oxo-propanoate (1a). Herein, we report an identified carbonyl reductase (CpKR) from Candida parapsilosis that displayed an excellent stereoselectivity toward the keto substituent at the C3-position of the 2-chloro-3-oxo-ester 1a. The engineered Escherichia coli cells harboring CpKR gene were directly applied for the asymmetric reduction of keto ester 1a with a space-time yield of 46 g L?1 d?1, which represents the highest productivity in bio-reduction of 1a reported so far. The isolated chiral alcohol products were then applied to the chemical synthesis of (2R,3S)-MPGM in 99% ee and a total yield of 76% in the two-step chemo-enzymatic reactions, which far exceeded the maximum theoretical yield (50%) of the existing industrial process based on a lipase-catalyzed resolution of racemic MPGM. This work provides a promising eco-friendly and cost-effective route toward industrial synthesis of pharmaceutically relevant diltiazem.
Chen, Cheng,Chen, Qi,Ni, Guo-Wei,Pan, Jiang,Xu, Jian-He,Xuan, Yang
(2021/07/02)

Catalytic transfer hydrogenation of ethyl levulinate to γ-valerolactone over supported MoS2catalysts
The hydrogenation of levulinate esters to γ-valerolactone (GVL) is an important step in the transformation of biomass into biofuels. It is attractive to develop new efficient systems for the catalytic transfer hydrogenation (CTH) of levulinate esters to value-added GVL. In this work, a series of MoS2-based supported catalysts were prepared via an impregnation method for the CTH of biomass-derived ethyl levulinate (EL) to GVL. By comprehensive characterization and catalytic measurements, we found that the CTH activity of EL to GVL is closely related to the MoS2 morphology and acid distribution on the support. Among the catalysts with different supports, the AC support with abundant Lewis acid sites and large surface area facilitated the high dispersion of low stacked MoS2 slabs, and the MoS2-acid synergistic catalysis contributed to the superior activity and selectivity. The conversion of EL and the selectivity of GVL reached 97.2% and 91.2% under optimized conditions over the MoS2/AC catalyst (230 °C, 1 MPa H2, 1.5 h), respectively. We also conducted reaction kinetic experiments to reveal the relationship between the active site of the MoS2/AC catalyst and its catalytic performance, and the plausible reaction pathway and mechanism over MoS2/AC was proposed. The catalytic performance gradually declined during recycling tests due to the oxidation of MoS2 and can be easily recovered by resulfuration.
Diao, Xinyong,Ji, Na,Jiang, Sinan,Liu, Caixia,Liu, Qingling,Liu, Zhenyu,Lu, Xuebin,Ma, Degang,Song, Chunfeng,Yu, Zhihao
p. 5062 - 5076
(2021/08/16)

NHC ligand-based half-sandwich iridium complexes: synthesis, structure and catalytic activity in acceptorless dehydrogenation and transfer hydrogenation
A set of neutral C,C-chelate half-sandwich iridium(iii) complexes have been prepared with NHC ligands that contain pendant aromatic rings as potentially chelating donor sites. The catalytic activity of such iridium complexes has been investigated for the acceptorless dehydrogenation (AD) reactions of alcohols and for the transfer hydrogenation reactions of ketones. The prepared iridium(iii) complexes show excellent catalytic activity for AD reactions of a wide range of secondary alcohols, and they are also shown to be effective for the synthesis of aldehydes from primary alcohols without the observation of undesired byproducts such as esters. Additionally, these complexes are also highly efficient in transfer hydrogenation of ketones and aldehydes, which give the alcohols in good yields under mild conditions. The exact structure and bonding mode of the NHC-based iridium complexes was identified using various spectroscopic methods and single crystal X-ray analysis.
Deng, Wei,Jin, Yan,Li, Rong-Jian,Liu, Zhen-Jiang,Wang, Yang,Yao, Zi-Jian
p. 19002 - 19010
(2021/10/29)

Furfural hydrodeoxygenation (HDO) over silica-supported metal phosphides – The influence of metal–phosphorus stoichiometry on catalytic properties
The gas-phase hydrodeoxygenation (HDO) of furfural, a model compound for bio-based conversion, was investigated over transition metal phosphide catalysts. The HDO activity decreases in the order Ni2P ≈ MoP > Co2P ≈ WP ? Cu3P > Fe2P. Nickel phosphide phases (e.g., Ni2P, Ni12P5, Ni3P) are the most promising catalysts in the furfural HDO. Their selectivity to the gasoline additives 2-methylfuran and tetrahydro-2-methylfuran can be adjusted by varying the P/Ni ratio. The effect of P on catalyst properties as well as on the reaction mechanism of furfural HDO were investigated in depth for the first time. An increase of the P stoichiometry weakens the furan-ring/catalyst interaction, which contributes to a lower ring-opening and ring-hydrogenation activity. On the other hand, an increasing P content does lead to a stronger carbonyl/catalyst interaction, i.e., to a stronger η2(C, O) adsorption configuration, which weakens the C1[sbnd]O1 bond (Scheme 1) in the carbonyl group and enhances the carbonyl conversion. Phosphorus species can also act as Br?nsted acid sites promoting C1[sbnd]O1 (Scheme 1) hydrogenolysis of furfuryl alcohol, hence contributing to higher production of 2-methylfuran.
Lan, Xuefang,Pestman, Robert,Hensen, Emiel J.M.,Weber, Thomas
p. 181 - 193
(2021/02/27)

Liquid phase hydrodeoxygenation of furfural over laponite supported NiPMoS nanocatalyst: Effect of phosphorus addition and laponite support
Unsupported and laponite supported NiPMoS catalysts were prepared under the hydrothermal method and investigated for liquid-phase hydrodeoxygenation of furfural in a high-pressure batch reactor at 423 ?K ? 463 ?K under 20 ?bar H2 pressure. The reaction significantly produced 94% of furfural conversion with 75% yield of 2-MF on NiPMoS catalyst whereas, NiPMoS/Lap catalyst exhibited 28% of 2-MF yield with complete conversion at 463 ?K under 20 ?bar H2 pressure in toluene solvent. The influence of process parameters such as reaction temperature, reactant volume, catalyst compositions, and hydrogen pressure on furfural conversion and product yield was investigated in detail. The high reactivity and synergetic effect of the NiPMoS catalyst are due to added phosphorus, which has a profound influence on the structure of the catalyst, thereby increasing surface acidity, basicity, hydrogen consumption, and a number of MoS2 fringes and the dispersion of MoS2 on the surface of the support. The catalysts were characterized based on HRTEM, H2, CO2, and NH3 TPD, FT–IR, FT–Raman, DRS UV–Vis, XRD, N2–physisorption, and TGA. Recyclability, N2–physisorption, and XRD results confirm the stability and practical applicability of the catalyst for industrial applications.
Krishnan, P. Santhana,Umasankar,Tamizhdurai,Mangesh,Shanthi
(2021/02/26)

Preparation of the Ru/HZSM-5 catalyst and its catalytic performance for the 2-pentanone hydrodeoxygenation reaction
Levulinic acid is an ideal model compound for complex oxygenated components in bio-oil. To assist the understanding of its hydrodeoxygenation (HDO) performance, it is necessary to investigate separately the HDO property of the ketonic carbonyl group and carboxyl group. Herein, 2-pentanone was selected as a model to study the HDO property of the ketonic carbonyl group. The Ru/HZSM-5 catalyst was prepared by an excessive impregnation method and its structure and acidity were characterized by H2-TPR, NH3-TPD, HRTEM, SEAD, Py-IR, TG-DSC, and ICP analyses. The effect of preparation conditions on the catalytic performance of Ru/HZSM-5 was studied; the suitable preparation conditions were determined as follows: a calcination temperature of 450 °C, a calcination time of 3 h, a reduction temperature of 350 °C, and a reduction time of 4 h. The catalytic performance of Ru/HZSM-5 for the 2-pentanone HDO reaction was evaluated; pentane selectivity of 77.7% at a 2-pentanone conversion of 91.8% was achieved under the conditions of a reaction pressure of 5 MPa, a reaction temperature of 190 °C, a catalyst amount of 6 wt% and a reaction time of 6 h. 2-Pentanone HDO follows the reaction path of 2-pentanone hydrogenation to 2-pentanol and then 2-pentanol dehydration and hydrogenation to the target product pentane. The acidity of the catalyst plays a certain role in influencing its catalytic performance: Lewis acid sites show high activity for activating C-O bonds and Br?nsted acid sites are the key to accelerate the further dehydration of 2-pentanol and hydrogenation to alkanes.
An, Hualiang,Wang, Yanji,Xi, Xi,Yang, Ye,Zhao, Xinqiang
p. 17692 - 17698
(2021/10/04)

Hydrodeoxygenation of C4-C6 sugar alcohols to diols or mono-alcohols with the retention of the carbon chain over a silica-supported tungsten oxide-modified platinum catalyst
The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.
Betchaku, Mii,Cao, Ji,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
supporting information
p. 5665 - 5679
(2021/08/16)

Bioinspired Heterobimetallic Photocatalyst (RuIIchrom-FeIIIcat) for Visible-Light-Driven C-H Oxidation of Organic Substrates via Dioxygen Activation
We report a bioinspired heterobimetallic photocatalyst RuIIchrom-FeIIIcat and its relevant applications toward visible-light-driven C-H bond oxidation of a series of hydrocarbons using O2 as the O-atom source. The RuII center absorbs visible light near 460 nm and triggers a cascade of electrons to FeIII to afford a catalytically active high-valent FeIV═O species. The in situ formed FeIV═O has been employed for several high-impact oxidation reactions in the presence of triethanolamine (TEOA) as the sacrificial electron donor.
Goswami, Tapas,Kumar, Arun,Kumar, Sushil,Le Poul, Nicolas,Nautiyal, Divyanshu,Singh, Siddhant,Thetiot, Franck
supporting information
p. 16059 - 16064
(2021/11/13)

Reviving electrocatalytic reductive amination: A sustainable route from biogenic levulinic acid to 1,5-dimethyl-2-pyrrolidone
The electrocatalytic reductive amination offers a green pathway to N-containing platform and fine chemicals by using water as a hydrogen source and benign reaction conditions. However, systematic studies about suitable reaction conditions and application to biogenic substrates are rare. Here, we present the electrochemical transformation of levulinic acid to 1,5-dimethyl-2-pyrrolidone. Data from Smirnov et al. for the amination of conventional ketones were validated and extended by systematically investigating the impact of electrode material, substrate concentration, current density, solvent, electrolyte, and pH value. High substrate concentrations in an aqueous electrolyte with a high pH value enable imine formation and copper is identified as the most selective cathode material at current densities lower than 40 mA cm-2. The application of optimized reaction conditions to levulinic acid, followed by a short heating procedure for dehydrative ring closure, led to 1,5-dimethyl-2-pyrrolidone in 78% yield. The systematic approach of this work presents the first example of an electrochemical levulinic acid amination and provides a methodology for the benign synthesis of other N-containing species. This journal is
Holzh?user, F. Joschka,Kurig, Nils,Mürtz, Sonja D.,Palkovits, Regina
p. 8428 - 8433
(2021/11/17)

Polymer supported N-heterocyclic carbene ruthenium complex catalyzed transfer hydrogenation of ketones
Polymer supported N-heterocyclic carbene ruthenium complex (Poly-Ru-1) was synthesized by free radical polymerization of Ru complex monomer and divinylbenzene. The structure of Poly-Ru-1 was characterized by 13C solid-state NMR spectroscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS). 13C solid-state NMR spectra indicated the complete polymerization of Ru complex monomer. Poly-Ru-1 had the high specific surface area of 286.7 m2 g?1 and ruthenium was in +2 oxidation state. Poly-Ru-1 showed higher catalytic activity than the corresponding homogenous catalyst in transfer hydrogenation of ketones, which was attributed to the high dispersion of the active sites.
Wang, Rong,Qin, Li,Wang, Xin,Chen, Bihua,Zhao, Yun,Gao, Guohua
(2020/01/31)

Synthesis and characterization of new ruthenium(III) complexes derived from fluoreneamine-based Schiff base ligands and their catalytic activity in transfer hydrogenation of ketones
An easy and convenient synthesis of a new series of octahedral ruthenium(III) complexes bearing Schiff base ligands of general formula [RuCl2(EPh3)2(L)] (where E = P, As and L = O,N-donor Schiff bases) has been reported. The composition of all complexes has been unequivocally characterized by spectral (IR, UV-vis, EPR) and ESI-MS techniques. The substituted Schiff base ligands behave as bidentate O,N-donors and coordinate to ruthenium via the phenolic oxygen, the azomethine nitrogen. Complexes 1–6 have been proven to catalyze the transfer hydrogenation of linear, cyclic and aromatic ketones to their corresponding secondary alcohols in the presence of i-PrOH/KOH at 80 °C with conversion up to 99%. The effect of other variables on the transfer hydrogenation reaction such as solvent, base, and catalyst loading is also reported.
Balasubramani, Kasturi,Nagalakshmi, Veerasamy,Nandhini, Raja,Venkatachalam, Galmari
(2020/03/16)

Acetate Acetylacetonate Ampy Ruthenium(II) Complexes as Efficient Catalysts for Ketone Transfer Hydrogenation
The mixed acetate acetylacetonate (acac) ruthenium(II) phosphine complexes Ru(OAc)(acac)P2 [P2=(PPh3)2, Ph2P(CH2)4PPh2 (dppb)] were prepared by protonation of Ru(OAc)2(PPh3)2 with acetylacetone in dichloromethane. Reaction of the dppb derivative with 2-(aminomethyl)pyridine (ampy) affords the complex Ru(OAc)(acac)(ampy)(dppb), which converts to [Ru(acac)(ampy)(dppb)](OAc) in toluene at 90 °C. In the former derivative the ampy ligand is monodentate and coordinates through the NH2-moiety. The isolated acac complexes are active catalysts for the transfer hydrogenation of ketones with loadings as low as 0.01 mol%, the ampy having a strong accelerating effect. Several aromatic and aliphatic ketone substrates are converted to their corresponding alcohols, and different electronic influences through substituents on acetophenone are tolerated.
Hey, Daniela A.,Sauer, Michael J.,Fischer, Pauline J.,Esslinger, Eva-Maria H. J.,Kühn, Fritz E.,Baratta, Walter
p. 3537 - 3544
(2020/06/01)

Biaryl diphosphine ligands and their ruthenium complexes: Preparation and use for catalytic hydrogenation of ketones
Procedures for the preparation of the nucleophilic diphosphine ligands (R)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine) ((R)-Ph-Garphos, 2a) and (S)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine) ((S)-Ph-Garphos, 2b) were described. The ligands were used to prepare the ruthenium(II) Ph-Garphos complexes, chloro(p-cymene)(R)-(4,4′,6,6′-tetraamethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine)ruthenium(II) chloride ([RuCl(p-cymene)(R)-Ph-Garphos]Cl (3)) and chloro(p-cymene)(S)-(4,4′,6,6′-tetraamethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine)ruthenium(II) chloride ([RuCl(p-cymene)(S)-Ph-Garphos]Cl (4)). In the presence of the chiral diamine co-ligands (1R,2R)-1,2-diphenylethane-1,2-diamine (R,R-DPEN) and (1S,2S)-1,2-diphenylethane-1,2-diamine (S,S-DPEN), complexes 3 and 4 were found to be catalyst precursors for the enantioselective reduction of aryl ketones under mild conditions (room temperature and 3–4 atm of H2). The chiral alcohols were isolated in moderate to good yields and with enantioselectivities of up to 93percent. The ruthenium complexes chloro(p-cymene)(R)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(bis(3,5-dimethylphenyl)-phosphine)ruthenium(II) chloride ([RuCl(p-cymene)(R)-Xyl-Garphos]Cl (5)) and chloro(p-cymene)(S)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(bis(3,5-dimethylphenyl)-phosphine)ruthenium(II) chloride ([RuCl(p-cymene)(S)-Xyl-Garphos]Cl (6)) were also prepared and used as catalyst precursors for the hydrogenation of aryl ketones in the presence of (R,R)-DPEN and (S,S)-DPEN. Significant improvements in the enantioselectivities of the alcohols (up to 98percent ee.) were afforded. A combination of 6 and (S,S)-DPEN afforded (R)-1-(3-methoxyphenyl)ethanol in 89percent yield and with 95percent ee which was shown to be a suitable precursor for the preparation of (S)-rivastigmine.
Abdur-Rashid, Kamaluddin,Abdur-Rashid, Kareem,Dasgupta, Tara,Jia, Wenli,Lorraine, Shannen,Maragh, Paul
(2020/07/10)

Naphthyl-derived orthometalated RUII-NHC complexes: Effect of the NHC donors and/or substitution pattern on their synthesis and catalytic activity
Naphthyl-derived orthometalated RuII-NHC complexes have been developed for catalytic applications considering the stereoelectronic profiles of the NHC ligands, which can be modified easily via alteration of the NHC donors (ImNHC/1,2,4tzNHC) as well as their substitution pattern at the naphthyl ring. The azolium salts [(2a?c)-H]Br, precursors for the NHC ligands, react with [Ru(p-cymene)Cl2]2 in the presence of a base to deliver the ortho-metalated RuII-NHC complexes 3a?c with the general formula [(NHC)Ru(p-cymene)Br]. Orthometalation in these complexes can be exploited for further functionalization of the NHC ligands. This is depicted by the generation of the diphenylethylene-inserted isolable intermediate complex 4, from the reaction of 3a with diphenylacetylene in a 1:1 ratio, which eventually provides an annulated salt 5a-Br via reductive elimination. Gratifyingly, this process can also be made catalytic, which directly provides several mono-/bis-annulated cationic N-heterocyclic compounds starting from the imidazolium salts [(2a,b)-H]Br using [Ru(p-cymene)Cl2]2 as a precatalyst. Furthermore, subtle variations in the electronic profiles of the complexes 3a?c in combination with steric alterations are observed to influence their activity in the transfer hydrogenation of acetophenone, a model for the hydride transfer process. Among all the complexes studied here, complex 3b with an ImNHC donor at the second position of the naphthyl ring was identified as a superior catalyst in comparison to 3a,c featuring either a different NHC donor or substitution pattern with a low loading of 0.1 mol%.
Bauri, Somnath,Mallik, Anirban,Rit, Arnab
p. 3362 - 3374
(2020/10/02)

Chemoselective Electrochemical Hydrogenation of Ketones and Aldehydes with a Well-Defined Base-Metal Catalyst
Hydrogenation reactions are fundamental functional group transformations in chemical synthesis. Here, we introduce an electrochemical method for the hydrogenation of ketones and aldehydes by in situ formation of a Mn-H species. We utilise protons and electric current as surrogate for H2 and a base-metal complex to form selectively the alcohols. The method is chemoselective for the hydrogenation of C=O bonds over C=C bonds. Mechanistic studies revealed initial 3 e? reduction of the catalyst forming the steady state species [Mn2(H?1L)(CO)6]?. Subsequently, we assume protonation, reduction and internal proton shift forming the hydride species. Finally, the transfer of the hydride and a proton to the ketone yields the alcohol and the steady state species is regenerated via reduction. The interplay of two manganese centres and the internal proton relay represent the key features for ketone and aldehyde reduction as the respective mononuclear complex and the complex without the proton relay are barely active.
Fokin, Igor,Siewert, Inke
p. 14137 - 14143
(2020/10/12)

Direct Catalytic Conversion of Ethanol to C5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability
Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C5+ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd-promoted ZnO-ZrO2 catalyst. The sequence of reaction steps involved in the C5+ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross-aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C5+ ketones and the stability of the catalyst. A yield of >70 percent to C5+ ketones was achieved over a 0.1 percent Pd-ZnO-ZrO2 mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.
Bathena, Tanmayi,Goulas, Konstantinos A.,Gray, Michel,Guo, Mond F.,Kovarik, Libor,Martinez, Abraham,Ramasamy, Karthikeyan K.,Subramaniam, Senthil,Zhang, Xiao
p. 14550 - 14557
(2020/07/08)

COMPOSITIONS COMPRISING ODORLESS 1,2-PENTANEDIOL
Suggested is a cosmetic or pharmaceutical or detergent composition comprising 1,2 pentanediol, wherein said 1,2-pentanediol is obtained from a process comprising the follow ing steps: (a) providing at least one starting material selected from furfuryl alcohol and furfural; (b) reacting at least one of said starting materials with hydrogen in the presence of a heterogeneous catalyst to form 1,2-pentanediol, wherein said heterogeneous catalyst comprises: one or more metals selected from the group consisting of platinum, rhodium, ruthenium, nickel, palladium and iridium in metallic form and/or one or more compounds of metals selected from the group consisting of platinum, rhodium, ruthenium, nickel, palladium and iridium; and one or more support materials selected from the group consisting of activated carbon, aluminum oxide, silicon dioxide, and silicon carbide; and (c) removing the 1,2-pentanediol thus obtained from the reaction mixture.
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Paragraph 00316

(2020/04/25)

Efficient one-pot conversion of furfural into 2-methyltetrahydrofuran using non-precious metal catalysts
2-methyltetrahydrofuran, a biomass-derived chemical, is an important solvent with broad applications in organic chemistry. In this study, one-pot conversion of furfural into 2-methyltetrahydrofuran over non-precious metal catalysts was achieved by two-stage packing in a single reactor. The first stage converted furfural into 2-methylfuran over Co-based catalysts, and the second stage converted 2-methylfuran into 2-methyltetrahydrofuran over Ni-based catalysts. In order to reveal the reaction pathway and mechanism of this process, the hydrogenation reactions of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol were also carefully investigated. It is discovered that the conversion of furfural into 2-methylfuran could be catalyzed by Lewis acid sites, which was confirmed by a correlation between 2-methylfuran production rate and Lewis acid site density. Also, a mechanism on the direct conversion of furfural into 2-methylfuran without forming furfuryl alcohol as the intermediate is proposed. The experimental results of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol hydrogenation/hydrodeoxygenation over various catalysts provided valuable information on the future design of 2-methyltetrahydrofuran catalyst.
Jia, Xinxin,Li, Cuiqing,Liu, Ping,Song, Yongji,Sun, Luyang,Wang, Hong,Zhang, Chen,Zhang, Wei
(2020/04/29)

Mont-K10 Supported Fe(II) Schiff-Base Complex as an Efficient Catalyst for Hydrogenation of Ketones
Abstract: A new Fe(II) Schiff base complex anchored on mont-K10 (Fe@imine-mont-K10) was synthesized and extensively characterized by FTIR, powder X-ray diffraction, SEM–EDX, TEM, ESR, X-ray photoelectron spectroscopy (XPS), BET surface area measurement, solid state 29Si NMR and ICP-AES analysis. The catalytic activity of the complex was investigated for hydrogenation of ketones. The results indicated that it exhibited good catalytic activity for hydrogenation of aromatic as well as aliphatic ketones in i-PrOH/CH3CN (1:1) using Na-i-OPr as base at 80?°C resulting in moderate to excellent isolated yields (51–99%) of their corresponding products. The catalyst shows good reusability. Graphical Abstract: [Figure not available: see fulltext.].
Sultana, Samim,Borah, Geetika,Gogoi, Pradip. K.
p. 2142 - 2157
(2019/05/28)

Half?Sandwich (η6?p?Cymene) Ruthenium(II) complexes bearing 5?Amino?1?Methyl?3?Phenylpyrazole Schiff base ligands: Synthesis, structure and catalytic transfer hydrogenation of ketones
New (η6?p?cymene) ruthenium(II) complexes containing Schiff base ligands of the general composition [RuCl(η6?p?cymene)(L1?3)] have been synthesized. The complexes were characterized by analytical and spectral (FT?IR, UV–Vis, 1H NMR and 13C NMR) methods. The molecular structure of the representative complex [RuCl(η6?p?cymene)(L3)] 6 was determined by single crystal X?ray diffraction studies, revealing a pseudo-octahedral piano stool geometry around ruthenium(II) ion. Further, one of the complexes 6 was screened for their efficiency as a catalyst in the transfer hydrogenation of various ketones to alcohols in the presence of KOH and 2?propanol showed an excellent conversion up to 99%. Under the optimized conditions, the influence of base, reaction temperature and substrate scope was also reported.
Ramesh, Madhan,Venkatachalam, Galmari
p. 47 - 55
(2018/11/10)

Mild palladium-catalysed highly efficient hydrogenation of CN, C-NO2, and CO bonds using H2 of 1 atm in H2O
Here we present the first example of a mild and high-efficiency protocol enabling a process in water using 1 atm of H2 for the efficient and selective hydrogenation of nitriles, nitro compounds, ketones, and aldehydes to yield primary amines and alcohols with satisfactory yields of up to >99%. Several palladium-based nanoparticle catalysts were prepared from K2PdCl4 and ligands, and one of them was found to be the best and most suitable for the hydrogenation of CN, C-NO2, and CO bonds. In addition, the catalyst Pd-NPs can be easily recycled and reused without losing their activity and selectivity. A plausible mechanism for the hydrogenation of a CN bond was also proposed, representing the first example that possesses great potential for sustainable industrial purposes.
Liu, Yaxu,He, Shaopo,Quan, Ziyi,Cai, Huizhuo,Zhao, Yang,Wang, Bo
supporting information
p. 830 - 838
(2019/02/27)

Half-sandwich ruthenium(II)complexes containing O, N bidentate azo ligands: Synthesis, structure and their catalytic activity towards one-pot conversion of aldehydes to primary amides and transfer hydrogenation of ketones
The ruthenium(II)complexes of the general formula [Ru(η6?p?cymene)(Cl)(L1?5)](L = O, N-donors of biphenylazo derivatives), formed by reacting 2?(biphenylazo)phenol (HL1 ? HL4)and 1?(biphenylazo)naphthol ligands (HL5)with [{η6?p?cymene)RuCl}2(μ?Cl)2]have been synthesized. The compositions of the complexes have been established by IR, UV–Vis, 1H NMR spectral methods and X-ray crystallography. The synthesized complex could act as an efficient, reusable homogeneous catalyst for transformation of aldehydes to the corresponding primary amides in the presence of NH2OH·HCl, thus resulting an expansion of Beckmann rearrangement. The effect of solvent, base, temperature, time, catalyst loading and recyclability was also investigated. They also effectively catalyze the transfer hydrogenation reaction of various ketones with 2-propanol.
Nandhini, Raja,Venkatachalam, Galmari
p. 15 - 22
(2019/07/02)

Highly Efficient Abnormal NHC Ruthenium Catalyst for Oppenauer-Type Oxidation and Transfer Hydrogenation Reactions
The ruthenium complex [Ru(OAc)(a-PC)2]Br (3) containing two abnormal NHC ligands is obtained by reaction of Ru(OAc)2(PPh3)2 (1) with 1-(2-diphenylphosphinoethyl)-3-mesitylimidazolium bromide in the presence of NaOAc. Complex 3 catalyzes the Oppenauer-type oxidation of a number of alcohols at unrivalled reaction rates reaching TOFs up to 550 000 h-1, at low catalyst loadings (S/C higher than 10 000) and using acetone in stoichiometric amounts. Complex 3 is also highly active in the reverse transfer hydrogenation of several ketones with 2-propanol, displaying TOFs up to 600 000 h-1
Pardatscher, Lorenz,Hofmann, Benjamin J.,Fischer, Pauline J.,H?lzl, Sebastian M.,Reich, Robert M.,Kühn, Fritz E.,Baratta, Walter
p. 11302 - 11306
(2019/11/21)

Synthetic Versatility of Lipases: Application for Si-O Bond Formation and Cleavage
Several commercially available lipases were examined in a study on O-Si bond formation and cleavage applying silicon-based protecting groups and alcohols or the corresponding silyl ethers. With regard to deprotection, from silyl ether to the corresponding alcohol, only the solvent and the lipase were necessary. The influence of the protecting group, the lipase source, and the substituent was investigated to optimize the results. The TMS moiety could be removed in 24 hours of reaction at room temperature in aqueous systems (conv. up to 99%, depending on the substrate and lipase). The reverse reactions, that is, with the protection of the alcohols, were carried out in hexane using different silyl chlorides. The TMS, TES, and TBS moieties were successfully inserted in the primary and secondary alcohols without the need for dry conditions or an inert atmosphere, presenting conversions of up to 99%, depending on the substrate.
Brondani, Patrícia Bulegon,Mittersteiner, Mateus,Voigt, Morgana Aline,Klinkowski, Bruna Heloisa,Riva Scharf, Dilamara,De Jesus, Paulo Cesar
supporting information
p. 477 - 485
(2019/01/10)

Modeling and optimization of lipase-catalyzed hydrolysis for production of (S)-2-phenylbutyric acid enhanced by hydroxyethyl-β-cyclodextrin
An efficient reactive system was established to produce (S)-2-phenylbutyric acid (2-PBA) through the enzymatic enantioselective hydrolysis of 2-phenylbutyrate ester (2-PBAE) in aqueous medium. Lipase CALA from Canadian antarctica and hexyl 2-phenylbutyrate (2-PBAHE) were identified upon screening as the best enzyme and substrate, respectively. Adding hydroxyethyl-β-cyclodextrin (HE-β-CD) to improve the solubility of the substrate resulted in a 1.5 times increase in substrate conversion while retaining a high enantioselectivity compared with that when HE-β-CD was not added. The effects of lipase concentration, substrate concentration and HE-β-CD concentration, temperature, pH, and reaction time on enantiomeric excess and conversion rate were investigated, and the optimal conditions were identified using response surface methodology (RSM). Under the optimal conditions, namely 50 mg/mL lipase CALA, 30 mmol/L substrate, 60 mmol/L HE-β-CD, pH of 6.5, temperature of 83 °C and reaction time of 18 h, the enantiomeric excess and overall conversion rate were 96.05% and 27.28%, respectively. This work provides an efficient alternative method for improving the conversion of aromatic ester substrates by including β-cyclodextrin in an aqueous hydrolysis reaction system.
Zhang, Panliang,Cheng, Qing,Xu, Weifeng,Tang, Kewen
p. 96 - 103
(2019/05/27)

Glycerin and the laevulinic acid one-step process for preparing 1, 3 - propylene glycol and γ - e lactone method
The invention relates to a method for preparing 1,3-propylene glycol and gamma-valerolactone from glycerin and acetylpropionic acid by a one-step method. According to the method, a stainless steel high-pressure reactor with a volume of 50 ml is adopted; a catalyst used in the invention is Ru/C with its catalytic amount of 0.04g and with its composition by weight of Ru%=5%; and the rest is a carrier, namely activated carbon. A reaction material is a glycerin-acetylpropionic acid solution (concentration of acetylpropionic acid is 20 wt% and concentration ratio of acetylpropionic acid to glycerin is 1:1-10:1), and volume of the solution is 5 ml. A reaction solvent is water. Reaction temperature is 120-200 DEG C; reaction H2 pressure is 2-4 MPa; and reaction time is 0.5-12 h. In comparison with existing technologies for preparing 1,3-propylene glycol from glycerin, the invention is different in the following aspects: an acid reactant is added into the glycerin system; and by the utilization of a metal catalyst, the catalyst can cooperate with the acid reactant to selectively convert glycerin to 1,3-propylene glycol on one hand, and the acid reactant is simultaneously converted to a more valuable product on the other hand. The method provided by the invention has a wide application prospect.
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Paragraph 0019-0027

(2019/06/14)

Insights on the One-Pot Formation of 1,5-Pentanediol from Furfural with Co?Al Spinel-based Nanoparticles as an Alternative to Noble Metal Catalysts
CoAl-spinel nanoparticles prepared by liquid-feed flame spray pyrolysis (L?F FSP) and activated by reduction at different temperatures were used to investigate the hydrogenation process of furfural (FA) under mild conditions. Reduction of the spinel at 500 °C resulted in high FA conversion and selectivity to furfuryl alcohol (FFA, 81 % yield, in 1 hour). Reduction at higher temperatures (i. e., 700 and 850 °C) led to the direct formation of diols (i. e., 1,5-PeD and 1,2-PeD) from FA. The differences in activity are attributed to the formation of surface metallic cobalt nanoparticles upon reduction at high temperature. A maximum of 30 % 1,5-PeD was yielded after 8 hours of reaction under the optimized conditions of150 °C, 30 bar of H2 and with 40 mg of catalyst reduced at 700 °C. This is the first report on the direct catalytic conversion of furfural to1,5-pentanediol with a non-noble metal solid catalyst.
Gavilà,L?hde,Jokiniemi,Constanti,Medina,del Río,Tichit,álvarez
p. 4944 - 4953
(2019/09/17)

Hydro-Oxygenation of Furfural in the Presence of Ruthenium Catalysts Based on Al-HMS Mesoporous Support
Ru-containing catalyst based on an Al-HMS mesoporous aluminosilicate was synthesized. The mesoporous support and the catalyst on its basis were characterized by the methods of low-temperature desorption/adsorption of nitrogen, temperature-programmed desorption of ammonia, transmission electron microscopy, X-ray photoelectron microscopy, and energy-dispersive X-ray fluorescence analysis. The synthesized catalyst was investigated in the hydrodeoxygenation of the model compound of bio-oil, furfural, in the presence of H2O. The reaction was carried out at initial hydrogen pressures of 1–7 MPa at 200°C–300°C temperature range. The results revealed that the synthesized catalyst displayed a high activity in the hydrotransformation of furfural. The conversion was 100% in 1 hr at a 5 MPa hydrogen pressure and 200°C.
Roldugina,Shayakhmetov,Maksimov,Karakhanov
p. 1306 - 1315
(2019/11/03)

Transfer hydrogenation of ketones catalyzed by iridium-bulky phosphine complexes
The complexes [Ir(COD)(PR3)2]PF6 (R = PPh3 (1); R = PBn3 = tribenzylphosphine (2)), [Ir(COD)(PBn3)(PAn3)]PF6 (3) (PAn3 = Tri-orthoanisyl-phosphine) and cis-(P,P)-[IrH(COD)(PBn3){η2-P,C-(C6H4CH2)PBn2}]PF6 (4) are active in the transfer hydrogenation of ketones. However, complex (3) gives the best results in conversion toward the alcohol. Interestingly, commercial isopropanol was used as hydrogen source, without any drying treatment. In situ generated isopropoxide was used as base. An efficient conversion of a variety of ketones, aromatic or aliphatic, cyclic or linear, including molecules with conjugated or isolated C[dbnd]C moieties was achieved, thus reporting 12 examples of hydrogenated substrates. Ketones of higher steric hindrance could not be converted under the studied conditions. The experimental evidence indicates that the steric and electronic properties of the substrates are determinant in the observed conversions and performance of the system. For α,β-unsaturated ketones, preference toward the reduction of the C[dbnd]C bond was observed. However, the system shows chemoselectivity toward the carbonyl group in molecules which also bear an isolated C[dbnd]C moiety. With the results obtained, a pseudo first-order dependence of the reaction rate on the concentration of ketone was determined. Also, stoichiometric as well as in situ tests were performed to shed light into the reaction pathways possibly involved in the catalytic TH of ketones described herein (precursor 3, base and isopropyl alcohol as hydrogen source).
Landaeta, Vanessa R.,Rosa, Abel D. Salazar-La,Rodríguez-Lugo, Rafael E.
p. 303 - 311
(2017/09/06)

Synthesis of bimetallic complexes bridged by 2,6-bis(benzimidazol-2-yl) pyridine derivatives and their catalytic properties in transfer hydrogenation
A series of binuclear rhodium(i) and iridium(i) complexes with 2,6-bis(benzimidazol-2-yl) pyridine (bzimpy) derivatives were synthesized and characterized by elemental analysis and spectroscopic methods. The molecular and crystal structures of complex 3d were determined by the single crystal X-ray diffraction technique. Their monometallic analogues were prepared to compare the catalytic properties of the bimetallic complexes. To determine the catalyst properties that result in a cooperative, bimetallic enhancement of the reaction rate, the systematic variation of the intermetallic distance and the ligand donor properties of the bimetallic complexes were explored based on the transfer hydrogenation reactions of ketones.
Günnaz, Salih,G?k?e, Ayta? Gürhan,Türkmen, Hayati
p. 17317 - 17328
(2019/01/03)

Application of Ni(II) complexes of air stable Schiff base functionalized N-heterocyclic carbene ligands as catalysts for the transfer hydrogenation of aliphatic ketones
New air stable N-heterocyclic carbene functionalized Schiff base ligands (L) of the type 2-[-2-[3-(R)imidazol-1-yl]ethyliminomethyl]phenol [R = methyl (2), 2-pyridylmethyl (3)] were synthesized and characterized by NMR, IR, MS, and CHN analysis. Single crystal X-ray structural analysis of their Ni(II) complexes revealed square planar arrangement of the chelating ligands coordinated in tridentate (2, C^N^O) and tetradentate (3, N^C^N^O) modes around the metal. The three new isolated and fully characterized complexes were utilized as catalysts for the catalytic transfer hydrogenation of aliphatic ketones in 2-propanol as solvent and source of hydrogen. Based on 0.2 mol% catalyst concentration, the complexes showed activity for aliphatic ketones and 100% conversion (turnover number of 500) for cyclohexanone and all the aromatic ketones tested.
Abubakar, Samaila,Bala, Muhammad D.
p. 2913 - 2923
(2018/09/27)

Interplay between H-bonding and interpenetration in an aqueous copper(ii)-aminoalcohol-pyromellitic acid system: self-assembly synthesis, structural features and catalysis
Two new copper(ii) coordination compounds, [Cu(H1.5mdea)2]2(H2pma) (1a) and [{Cu2(μ-Hmdea)2}2(μ4-pma)]n·2nH2O (1b), were self-assembled at different temperatures from the same multicomponent reaction system, comprising copper(ii) nitrate, N-methyldiethanolamine (H2mdea), pyromellitic acid (H4pma), and potassium hydroxide. Products 1a and 1b were isolated as microcrystalline solids and fully characterized and their structures were established by single-crystal X-ray diffraction. Compound 1a features the bis-aminoalcohol(ate) monocopper(ii) units and H2pma2? anions that are multiply interconnected by strong H-bonds into a firm 2D H-bonded layer. Compound 1b reveals the bis-aminoalcoholate dicopper(ii) motifs that are interlinked by the μ4-pma4? spacers into a 3D + 3D interpenetrated metal-organic framework. From a topological perspective, both networks of 1a and 1b are uninodal and driven by similar 4-connected H2pma2? or pma4? nodes, but result in distinct sql and dia topologies, respectively. Compound 1a was applied as an efficient catalyst for two model cycloalkane functionalization reactions: (1) oxidation by H2O2 to form cyclic alcohols and ketones and (2) hydrocarboxylation by CO/H2O and S2O82? to form cycloalkanecarboxylic acids. The substrate scope, effects of various reaction parameters, selectivity and mechanistic features were also investigated.
Fernandes, Tiago A.,Kirillova, Marina V.,André, Vania,Kirillov, Alexander M.
p. 16674 - 16683
(2018/12/05)

Catalytic conversion of biomass-derived levulinic acid into alcohols over nanoporous Ru catalyst
Several Ru-based catalysts were investigated under the same reaction conditions for levulinic acid (LA) hydrogenation. All LA conversion was 100% with the catalysts but the selectivity was different. The mina product was ?-valerolactone (GVL) by using powder Ru, Ru/C, and Ru/Al2O3 catalysts, yet it was 2-butanol (2-BO) and 2-pentanol (2-PO) with nanoporous Ru (NP-Ru) as catalyst. Several other nanoporous metal, e.g., Ni, Fe, Co, and Cu catalysts have been investigated for LA hydrogenation under the same reaction conditions, but the main product was still GVL with little 2-BO and 2-PO accompanied by serious leaching of catalyst. Results showed that NP-Ru play a positive role in the activation of GVL, which is generally difficult to achieve with mono-metallic catalysts unless under strict reaction ocnditions.
Lv, Jinkun,Rong, Zeming,Sun, Liming,Liu, Chengyun,Lu, An-Hui,Wang, Yue,Qu, Jingping
p. 975 - 979
(2018/03/05)

Aqueous Hydrogenation of Levulinic Acid to 1,4-Pentanediol over Mo-Modified Ru/Activated Carbon Catalyst
A highly efficient and green process was developed for direct conversion of levulinic acid into 1,4-pentanediol over Mo-modified Ru/activated carbon (AC) catalyst in a continuous fixed-bed reactor. The Ru–MoOx/AC catalyst was found to be efficient for the aqueous-phase hydrogenation of levulinic acid to 1,4-pentanediol, whereby a high yield (96.7 mol %) of 1,4-pentanediol was obtained under mild reaction conditions (70 °C, 4 MPa H2).
Cui, Jinglei,Tan, Jingjing,Zhu, Yulei,Cheng, Fangqin
p. 1316 - 1320
(2018/03/21)

Encapsulation of Crabtree's Catalyst in Sulfonated MIL-101(Cr): Enhancement of Stability and Selectivity between Competing Reaction Pathways by the MOF Chemical Microenvironment
Crabtree's catalyst was encapsulated inside the pores of the sulfonated MIL-101(Cr) metal–organic framework (MOF) by cation exchange. This hybrid catalyst is active for the heterogeneous hydrogenation of non-functionalized alkenes either in solution or in the gas phase. Moreover, encapsulation inside a well-defined hydrophilic microenvironment enhances catalyst stability and selectivity to hydrogenation over isomerization for substrates bearing ligating functionalities. Accordingly, the encapsulated catalyst significantly outperforms its homogeneous counterpart in the hydrogenation of olefinic alcohols in terms of overall conversion and selectivity, with the chemical microenvironment of the MOF host favouring one out of two competing reaction pathways.
Grigoropoulos, Alexios,McKay, Alasdair I.,Katsoulidis, Alexandros P.,Davies, Robert P.,Haynes, Anthony,Brammer, Lee,Xiao, Jianliang,Weller, Andrew S.,Rosseinsky, Matthew J.
supporting information
p. 4532 - 4537
(2018/03/26)

Palladium–Ruthenium Catalyst for Selective Hydrogenation of Furfural to Cyclopentanol
Bimetallic Pd–Ru/C catalyst was shown to be much more active in the aqueous-phase hydrogenation of furfural (473 K, 8 MPa) in comparison with both Pd/C and Ru/C catalysts. The enhanced hydrogenation activity manifested itself as an increased yield of cyclopentanol (77%) at a complete conversion of furfural. The observed synergistic effect between palladium and ruthenium in the tested reaction can be related to changes in the electronic state and particle size of supported metals upon interaction with each other and the Pd–Ru alloy formation.
Mironenko,Belskaya,Lavrenov,Likholobov
p. 339 - 346
(2018/06/11)

CATALYST FOR ONE CARBON-REDUCTION REACTION, AND METHOD FOR PRODUCING ONE CARBON-REDUCTION COMPOUND USING THE SAME
PROBLEM TO BE SOLVED: To provide a method for producing selectively a one carbon-reduction compound, using a compound having a primary hydroxy group, a carboxyl group, or an alkoxycarbonyl group, or a lactone compound, as a substrate. SOLUTION: A method of obtaining a one carbon-reduction compound includes the reaction of a compound as a substrate represented by formula (1-1) or (1-2) or (1-3) with hydrogen in the presence of a catalyst in which a metal selected from Ru, Rh, Pd, Ir, and Pt is supported on a support selected from CeO2, hydroxyapatite, ZrO2, TiO2, hydrotalcite, SiO2, MgO, and Al2O3 (R1-R3 independently represent H, a substituted/unsubstituted monovalent hydrocarbon group, or a monovalent group in which two or more hydrocarbon groups are bound together through a linking group; R1-R3 may form a ring with adjacent carbon; L is a substituted/unsubstituted divalent hydrocarbon group or the like; and n is an integer of 0 or greater). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0067; 0068; 0069

(2018/07/28)

Ru-Photoredox-Catalyzed Decarboxylative Oxygenation of Aliphatic Carboxylic Acids through N-(acyloxy)phthalimide
Decarboxylative aminoxylation of aliphatic carboxylic acid derivatives with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) in the presence of ruthenium photoredox catalysis is reported. The key transformation entails a highly efficient photoredox catalytic cycle using Hantzsch ester as a reductant. The ensuing alkoxyamine can be readily converted to the corresponding alcohol in one pot, representing an alternative approach to access aliphatic alcohols under photoredox conditions.
Zheng, Chao,Wang, Yuting,Xu, Yangrui,Chen, Zhen,Chen, Guangying,Liang, Steven H.
supporting information
p. 4824 - 4827
(2018/08/24)

Supported cobalt catalysts for the selective hydrogenation of ethyl levulinate to various chemicals
A highly active and selective cobalt catalyst was developed for the hydrogenation of biomass-derived ethyl levulinate (EL) to γ-valerolactone (GVL), ethyl 4-hydroxypentanoate (EHP), 1,4-pentanediol (1,4-PDO) and 2-methyltetrahydrofuran (2-MTHF), which are considered to be value-added chemicals and important biofuels. The effects of reaction time, reaction temperature, catalyst amount and solvent on its catalytic performance were investigated. In addition, the reaction pathway was studied as well. It was found that the selectivity of GVL, 1,4-PDO and 2-MTHF on Co/ZrO2 can be easily tuned by changing reaction conditions, and can reach as high as 94%, 78% and 77%, respectively. The product selectivity is also significantly affected by the catalyst support. With SBA-15 as the support, the selectivity of EHP can reach 90%. Moreover, Co/ZrO2 gave an extraordinarily high GVL productivity of 1.50 mol gmetal-1 h-1 and displayed excellent stability and reusability. Interestingly, coke has a positive effect on the enhancement of GVL yield. AL dimers and trimers were identified as the coke species in the hydrogenation of EL. As far as we know, this is the first work conducting the flexible transformation of EL on cobalt catalysts.
Cen, Youliang,Zhu, Shanhui,Guo, Jing,Chai, Jiachun,Jiao, Weiyong,Wang, Jianguo,Fan, Weibin
p. 9152 - 9160
(2018/03/21)

Half-Sandwich Osmium(II) Complexes with Bidentate N,N-Chelating Ligands and Their Use in the Transfer Hydrogenation of Ketones
The reaction of appropriate N,N-bidentate ligands with the [(η6-p-cymene)Os(μ-Cl)Cl]2dimer (p-cymene = C10H14), followed by metathesis reaction with NH4PF6, gave the new osmium(II) arene complex salts [(η6-p-cymene)OsCl(C5H4N-2-CH=N–R)]PF6, where [R = tert-butyl (1), isopropyl (2), 2,6-dimethylphenyl (3), or 2,6-diisopropylphenyl (4)]. The dimer was also reacted with the N,N′-bidentate ligands di-(2-pyridyl)amine (5), 4-phenyl-3,6-di(2-pyridyl)pyridazine (6), 4,4′-di-tert-butyl-2, 2′-bipyridine (7), and 5,5′-dimethyl-2,2′-bipyridine (8). In addition, the reaction of the precursor [(η6-C6H6)Os(μ-Cl)Cl]2with the N,N′-bidentate ligands gave [(η6-C6H6)OsCl(N,N)]2where N,N = 4,4′-di-tert-butyl-2,2′-bipyridine (9), 5,5′-dimethyl-2,2′-bipyridine (10), 3,6-bis(2-pyridyl)-4-phenyl pyridazine (11), or di-(2-pyridyl)amine (12). The compounds were characterized by using1H and13C NMR, UV/Vis, FTIR spectroscopy and elemental analysis. The single-crystal X-ray structures for compounds 1, 4, 8, 10, 11, and 12 showed that the osmium(II) complexes adopted the classical three-legged piano stool geometry. These osmium(II) compounds were found to be effective catalysts for the transfer hydrogenation of ketones into alcohols with NaOH as base and 2-propanol as the solvent and hydrogen source. A range of cyclic, aromatic, and aliphatic ketones was studied and good turnover numbers achieved.
Gichumbi, Joel M.,Omondi, Bernard,Friedrich, Holger B.
p. 915 - 924
(2017/02/15)

Bioorganometallic chemistry: Co-factor regeneration, enzyme recognition of biomimetic 1,4-NADH analogs, and organic synthesis; tandem catalyzed regioselective formation of N-substituted-1,4-dihydronicotinamide derivatives with [Cp*Rh(bpy)H]+, coupled to chiral S-alcohol formation with HLADH, and engineered cytochrome P450s, for selective C-H oxidation reactions
Two novel tandem catalysis approaches for the chiral synthesis of S-alcohols from reduction of their prochiral ketones with Horse Liver Alcohol Dehydrogenase (HLADH), and selective C-H oxidation reactions with protein engineered Cytochrome P450s, are presented. We utilized a co-factor regeneration procedure with three biomimetic NAD+ models that do not contain the pyrophosphate, nor the adenosine group, and either/or a ribose, N-1-benzylnicotinamide triflate, 1, N-4-methoxybenzylnicotinamide triflate, 2, and β-nicotinamide-5′-ribose methyl phosphate, 3, in conjunction with in situ formed [Cp*Rh(bpy)H]+ from [Cp*Rh(bpy)(H2O)]2+ (Cp*?=?η5-C5Me5, bpy?=?2,2'-bipyridyl) and the hydride source, sodium formate, to regioselectively provide their 1,4-NADH analogs, N-benzyl-1,4-dihydronicotinamide, 4, N-4-methoxybenzyl-1,4-dihydronicotinamide, 5, and 1,4-dihydronicotinamide-5′-ribose methylphosphate, 6. Surprisingly, the 1,4-NADH biomimics, 4 and 6, were recognized, in the second tandem catalysis approach, by the natural 1,4-NADH dependent enzyme, HLADH, for catalyzed, highly enantioselective conversions of prochiral ketones to chiral S-alcohols. For example, with phenethylmethyl ketone and benzylmethyl ketone, the corresponding chiral alcohols were formed in >93% ee (S-enantiomer). Thus, 1,4-NADH biomimetic model recognition by HLADH does not significantly depend on the presence of the ribose, pyrophosphate, or adenosine groups to provide chiral products. We will also propose a plausible active site (HLADH)Zn-H intermediate, generated via a hydride transfer from bound 4/6 to Zn, for the enzymatic reduction of prochiral aryl/alkyl ketones to their chiral aryl/alkyl S-alcohols. Furthermore, the use of protein engineered cytochrome P450 enzymes provided improved molecular recognition of the above mentioned 1,4-NADH biomimetic co-factors, 4 and 5, for selective C-H oxidation reactions. For example, 1,4-NADH dependent mutants of natural 1,4-NAD(P)H dependent P450 BM-3 and 1,4-NADH dependent P450 CAM, with biomimetic co-factors 4 and 5, provided selective oxidation of p-nitrophenoxydecanoic acid to ω-oxydecanocarboxylic acid and p-nitrophenol, via C-H hydroxylation and β-hydrogen elimination, while oxidation of camphor provided hydroxycamphor, respectively. We will discuss the various parameters that effect molecular recognition of the biomimics, including protein engineering of both P450 BM-3 and P450 CAM enzymes, while determining the effect of the co-factor regeneration procedure on HLADH and P450 enzyme activity. These important observations have created new paradigms for the synthesis of organic compounds of interest, with the economically more favorable biomimics of NAD+, 1,4-NADH, and 1,4-NAD(P)H as co-factors, in tandem with the use of [Cp*Rh(bpy)(H)]+ as a regioselective catalytic reagent for co-factor regeneration.
Lo, H. Christine,Ryan, Jessica D.,Kerr, John B.,Clark, Douglas S.,Fish, Richard H.
p. 38 - 52
(2017/05/08)

Catalytic transfer hydrogenation of levulinic acid to γ-valerolactone over a bifunctional tin catalyst
The conversion of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) is important but extremely challenging due to the use of noble metal catalysts and high-pressure gaseous hydrogen. Here we describe the transfer hydrogenation of LA to GVL using 2-propanol as hydrogen donor over a Sn modified silica catalyst (SnO2/SBA-15) which gives high LA conversion (85.1%) and GVL selectivity (95.2%). Key to this success is employing a simply synthesized Sn-modified silica catalyst (SnO2/SBA-15) with both Lewis and Br?nsted acidity, which could synergistically catalyze the tandem steps of hydrogen transfer and esterification, leading to successful transformation of LA to GVL.
Xu, Shaodan,Yu, Deqing,Ye, Tao,Tian, Panpan
p. 1026 - 1031
(2017/01/13)

Ru(II) mediated C[sbnd]H activation of 1-(biphenylazo)naphtholSynthesis and catalytic evaluation for transfer hydrogenation of ketones
New cyclometalated ruthenium(II) complexes of the type [Ru(L)(CO)(EPh3)2] (L?=?di-anionic CNO- donor of 1-(biphenylazo)naphthol; E?=?P, As) have been synthesized by the reaction using [RuHCl(CO)(EPh3)3] (E?=?P, As) with 1-(biphenylazo)naphthol ligand (H2L). The 1-(biphenylazo)naphthol ligand and ruthenium complexes are characterized by analytical, spectral (FT–IR, UV–Vis, 1H NMR and 31P NMR) methods. The molecular structure of ruthenium complex 1 was further confirmed by single crystal X-ray diffraction method. The catalytic efficiency of ruthenium complex 1 was evaluated for the transfer hydrogenation of various ketones to alcohols with excellent conversion up to 99% in the presence of i-PrOH/KOH at 82?°C.
Ramesh, Madhan,Prabusankar, Ganesan,Venkatachalam, Galmari
p. 89 - 94
(2017/04/06)

Double-active sites cooperatively catalyzed transfer hydrogenation of ethyl levulinate over a ruthenium-based catalyst
Presently, designing high-performance catalyst systems for the sustainable production of chemicals through biomass conversions is of significant importance for large-scale practical application. As for heterogeneous catalysts, the high dispersion of active species can play a vital role in guaranteeing their superior performance. In this regard, the combination of active species with a favorable support matrix is crucial for achieving highly dispersive character of active species and the formation of cooperation between them. Herein, we first synthesized a novel ruthenium-based catalyst, Ru/Zn-Al-Zr layered double hydroxide (Ru/ZnAlZr-LDH), which was employed in the transfer hydrogenation of biomass-derived ethyl levulinate (EL) into γ-valerolactone (GVL) using 2-propanol as hydrogen donor. Extensive characterizations revealed that the interaction between Ru species and the ZnAlZr-LDH matrix helped enhance the dispersion of Ru species on the LDH and also determined the nature of electron-rich Ru species. Furthermore, a cooperative effect between double-active sites on the catalyst, e.g. a large amount of surface hydroxyl groups and highly dispersive electron-rich Ru species, was beneficial to the formation of both activated six-membered ring transition state and active ruthenium-hydride species in the course of EL transfer hydrogenation, thereby resulting in an unparalleled activity with a fastest GVL formation rate of 1250 μmol gcat?1 min?1 to date, with respect to other Zr- or Ru-based catalysts previously reported.
Gao, Zhi,Fan, Guoli,Yang, Lan,Li, Feng
p. 181 - 190
(2017/10/30)