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Synthesis, biotransformation and biological activity of halolactones obtained from β-ionone
Commercially available β-ionone was used as a starting material for a four-step chemical synthesis of three new γ-halolactones. During these processes one known (β-ionol) and some new compounds (γ,δ-unsaturated ester, γ,δ-unsaturated acid, chloro-, bromo- and iodo-lactone) were obtained. In the last step, halolactones were converted into a hydroxylactone by several fungal strains (Fusarium species, Syncephalastrum racemosum, Botrytis cinerea). Most of the selected microorganisms transformed these lactones by the hydrolytic dehalogenation. The synthetic halolactones and the hydroxylactone obtained during biotransformation inhibited growth of some bacteria, yeasts and fungi and showed deterrent activity against aphids Myzus persicae.
Grabarczyk, Malgorzata,Wiska, Katarzyna,McZka, Wanda,Zarowska, Barbara,MacIejewska, Gabriela,Dancewicz, Katarzyna,Gabrys, Beata,Aniol, Miroslaw
p. 637 - 644
(2016)
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Graphene oxide as a catalyst for the diastereoselective transfer hydrogenation in the synthesis of prostaglandin derivatives
Modification of GO by organic molecules changes its catalytic activity in the hydrogen transfer from i-propanol to enones, affecting the selectivity to allyl alcohol and diastereoselectivity to the resulting stereoisomers. It is noteworthy the system does not contain metals and is recyclable.
Coman, Simona M.,Podolean, Iunia,Tudorache, Madalina,Cojocaru, Bogdan,Parvulescu, Vasile I.,Puche, Marta,Garcia, Hermenegildo
p. 10271 - 10274
(2017)
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Transformations of α- And β-ionones in the presence of Al 2O3 in a supercritical solvent in a flow reactor
The reactivity of α- and β-ionones under the supercritical conditions in a flow type reactor in the presence of Al2O3 at 200-230 C was studied. α-Ionone was reduced to α-ionol, while β-ionol was unstable already at 200 C and underwent dehydration. The secondary reaction products were the corresponding megastigmatrienes.
Anikeev,Sivcev,Volcho,Salakhutdinov
p. 1940 - 1942
(2013)
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Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
supporting information
p. 21176 - 21182
(2020/09/17)

Capturing the Monomeric (L)CuH in NHC-Capped Cyclodextrin: Cavity-Controlled Chemoselective Hydrosilylation of α,β-Unsaturated Ketones
The encapsulation of copper inside a cyclodextrin capped with an N-heterocyclic carbene (ICyD) allowed both to catch the elusive monomeric (L)CuH and a cavity-controlled chemoselective copper-catalyzed hydrosilylation of α,β-unsaturated ketones. Remarkably, (α-ICyD)CuCl promoted the 1,2-addition exclusively, while (β-ICyD)CuCl produced the fully reduced product. The chemoselectivity is controlled by the size of the cavity and weak interactions between the substrate and internal C?H bonds of the cyclodextrin.
Bistri-Aslanoff, Olivia,Derat, Etienne,Leloux, Sébastien,Leyssens, Tom,Ménand, Micka?l,Meijide Suárez, Jorge,Riant, Olivier,Roland, Sylvain,Sollogoub, Matthieu,Xu, Guangcan,Zhang, Pinglu,Zhang, Yongmin
supporting information
p. 7591 - 7597
(2020/03/23)

Fungi-mediated biotransformation of the isomeric forms of the apocarotenoids ionone, damascone and theaspirane
In this work, we describe a study on the biotransformation of seven natural occurring apocarotenoids by means of eleven selected fungal species. The substrates, namely ionone (α-, β- and γ-isomers), 3,4-dehydroionone, damascone (α- and β-isomers) and theaspirane are relevant flavour and fragrances components. We found that most of the investigated biotransformation reactions afforded oxidized products such as hydroxy- keto- or epoxy-derivatives. On the contrary, the reduction of the keto groups or the reduction of the double bond functional groups were observed only for few substrates, where the reduced products are however formed in minor amount. When starting apocarotenoids are isomers of the same chemical compound (e.g., ionone isomers) their biotransformation can give products very different from each other, depending both on the starting substrate and on the fungal species used. Since the majority of the starting apocarotenoids are often available in natural form and the described products are natural compounds, identified in flavours or fragrances, our biotransformation procedures can be regarded as prospective processes for the preparation of high value olfactory active compounds.
Serra, Stefano,De Simeis, Davide
(2019/01/16)

Selective Base-free Transfer Hydrogenation of α,β-Unsaturated Carbonyl Compounds using iPrOH or EtOH as Hydrogen Source
Commercially available Ru-MACHOTM-BH is an active catalyst for the hydrogenation of several functional groups and for the dehydrogenation of alcohols. Herein, we report on the new application of this catalyst to the base-free transfer hydrogenation of carbonyl compounds. Ru-MACHOTM-BH proved to be highly active and selective in this transformation, even with α,β-unsaturated carbonyl compounds as substrates. The corresponding aliphatic, aromatic and allylic alcohols were obtained in excellent yields with catalyst loadings as low as 0.1–0.5 mol % at mild temperatures after very short reaction times. This protocol tolerates iPrOH and EtOH as hydrogen sources. Additionally, scale up to multi-gram amounts was performed without any loss of activity or selectivity. An outer-sphere mechanism has been proposed and the computed kinetics and thermodynamics of crotonaldehyde and 1-phenyl-but-2-en-one are in perfect agreement with the experiment.
Farrar-Tobar, Ronald A.,Wei, Zhihong,Jiao, Haijun,Hinze, Sandra,de Vries, Johannes G.
supporting information
p. 2725 - 2734
(2018/02/28)

Creating Hierarchical Pores by Controlled Linker Thermolysis in Multivariate Metal-Organic Frameworks
Sufficient pore size, appropriate stability, and hierarchical porosity are three prerequisites for open frameworks designed for drug delivery, enzyme immobilization, and catalysis involving large molecules. Herein, we report a powerful and general strategy, linker thermolysis, to construct ultrastable hierarchically porous metal-organic frameworks (HP-MOFs) with tunable pore size distribution. Linker instability, usually an undesirable trait of MOFs, was exploited to create mesopores by generating crystal defects throughout a microporous MOF crystal via thermolysis. The crystallinity and stability of HP-MOFs remain after thermolabile linkers are selectively removed from multivariate metal-organic frameworks (MTV-MOFs) through a decarboxylation process. A domain-based linker spatial distribution was found to be critical for creating hierarchical pores inside MTV-MOFs. Furthermore, linker thermolysis promotes the formation of ultrasmall metal oxide nanoparticles immobilized in an open framework that exhibits high catalytic activity for Lewis acid-catalyzed reactions. Most importantly, this work provides fresh insights into the connection between linker apportionment and vacancy distribution, which may shed light on probing the disordered linker apportionment in multivariate systems, a long-standing challenge in the study of MTV-MOFs.
Feng, Liang,Yuan, Shuai,Zhang, Liang-Liang,Tan, Kui,Li, Jia-Luo,Kirchon, Angelo,Liu, Ling-Mei,Zhang, Peng,Han, Yu,Chabal, Yves J.,Zhou, Hong-Cai
supporting information
p. 2363 - 2372
(2018/02/19)

SELECTIVE REDUCTION OF ALDEHYDES AND KETONES
The present invention relates to a selective reduction of specific aldehydes and ketones to their corresponding alcohols.
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Page/Page column 46; 47

(2017/12/01)

Transfer Hydrogenation of Carbonyl Derivatives Catalyzed by an Inexpensive Phosphine-Free Manganese Precatalyst
A very simple and inexpensive catalytic system based on abundant manganese as transition metal and on an inexpensive phosphine-free bidendate ligand, 2-(aminomethyl)pyridine, has been developed for the reduction of a large variety of carbonyl derivatives with 2-propanol as hydrogen donor. Remarkably, the reaction proceeds at room temperature with low catalyst loading (down to 0.1 mol %) and exhibits a good tolerance toward functional groups. High TON (2000) and TOF (3600 h-1) were obtained.
Bruneau-Voisine, Antoine,Wang, Ding,Dorcet, Vincent,Roisnel, Thierry,Darcel, Christophe,Sortais, Jean-Baptiste
supporting information
p. 3656 - 3659
(2017/07/15)

Selective Hydrogenation of α,β-Unsaturated Aldehydes and Ketones by Air-Stable Ruthenium NNS Complexes
The selective hydrogenation of the carbonyl functionality of α,β-unsaturated aldehydes and ketones is catalysed by ruthenium dichloride complexes bearing a tridentate NNS ligand as well as triphenylphosphine. The tridentate ligand backbone is flexible, as evidenced by the equilibrium observed in solution between the cis- and trans-isomers of the dichloride precatalysts, as well as crystal structures of several of these complexes. The complexes are activated by base in the presence of hydrogen and readily hydrogenate carbonyl functionalities under mild conditions. Despite the activation by base, side reactions are negligible, even for aldehyde substrates, because of the low amount of base. Thus, the corresponding allylic alcohols can be isolated in very good yields on a 10–25 mmol scale. Turnover numbers up to 200 000 were achieved.
Puylaert, Pim,van Heck, Richard,Fan, Yuting,Spannenberg, Anke,Baumann, Wolfgang,Beller, Matthias,Medlock, Jonathan,Bonrath, Werner,Lefort, Laurent,Hinze, Sandra,de Vries, Johannes G.
p. 8473 - 8481
(2017/06/28)

Rapid probing of the reactivity of P450 monooxygenases from the CYP116B subfamily using a substrate-based method
Developing a detailed understanding of the reactivity of self-sufficient Type IV P450 monooxygenases, four types of O-methylated substrates were designed as probes, including monoterpenes, cycloalkanes, aromatic compounds and steroids, and the efficiency of their oxyfunction was determined using a colorimetric assay which was based on the reaction between the enzymatic demethylation product, formaldehyde, and Purpald dye. The activity-based fingerprints of new P450RpMO, P450ArMO and P450CtMO (CYP116B members) indicated that CYP116B P450s preferentially oxidize substrates with aromatic components. Moreover, the hydroxylated products were detected based on the preference results. This rapid and efficient strategy, when coupled with GCMS, enables the exploration of the reactivity of other CYP116B members.
Li, Ren-Jie,Xu, Jian-He,Yin, Yue-Cai,Wirth, Nicolas,Ren, Jiang-Meng,Zeng, Bu-Bing,Yu, Hui-Lei
supporting information
p. 8928 - 8934
(2016/10/13)

Industrial manufacturing method for damascenone
The invention provides an industrial manufacturing method for damascenone. The industrial manufacturing method for damascenone is characterized in that ionone serves as an initial raw material, and the target product damascenone is obtained after reducing, a rearrangement reaction, hydrolysis, oxidation and a hydrolysis reaction. The production process and the synthesis route are optimized; in the production process, there are fewer side reactions, aftertreatment is convenient, production conditions are mild, and the method is suitable for industrial production patterns.
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Paragraph 0062-0064

(2017/04/21)

HYDROGENATION OF ALDEHYDE OR KETONE COMPOUNDS WITH FE/TRIDENTATE LIGANDS COMPLEXES
The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of Fe complexes with tridentate ligands, having one amino or imino coordinating group and two phosphino coordinating groups, in hydrogenation processes for the reduction of ketones or aldehydes, into the corresponding alcohol or diol, respectively.
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Page/Page column 25-27

(2017/01/02)

Eco-friendly stereoselective reduction of α,β-unsaturated carbonyl compounds by Er(OTf)3/NaBH4 in 2-MeTHF
An operationally simple and environmentally benign catalytic procedure has been developed to selectively reduce different α,β-unsaturated ketones. The corresponding allylic alcohols are obtained with high chemo- and diastereoselectivity using Er(OTf)3 and NaBH4 in 2-MeTHF. This protocol reduces the amount of catalyst and NaBH4 needed, compared to classical procedures and the stages of extraction/purification are carried out in aqueous solutions avoiding the use of toxic solvents. Taking into account that Er(OTf)3 can be considered even less toxic than table salt and the 'greenness' of 2-MeTHF as a solvent, the system Er(OTf)3/2-MeTHF can be proposed as a cheap, efficient, and environmentally sustainable reduction system for the synthesis of allylic alcohols.
Nardi, Monica,Sindona, Giovanni,Costanzo, Paola,Oliverio, Manuela,Procopio, Antonio
p. 1132 - 1135
(2015/02/19)

Versatile iridicycle catalysts for highly efficient and chemoselective transfer hydrogenation of carbonyl compounds in water
Cyclometalated iridium complexes are shown to be highly efficient and chemoselective catalysts for the transfer hydrogenation of a wide range of carbonyl groups with formic acid in water. Examples include α-substituted ketones (α-ether, α-halo, α-hydroxy, α-amino, α-nitrile or α-ester), α-keto esters, β-keto esters and α,β-unsaturated aldehydes. The reduction was carried out at substrate/catalyst ratios of up to 50000 at pH 4.5 and required no organic solvent. The protocol provides a practical, easy and efficient way for the synthesis of β-functionalised secondary alcohols, such as β-hydroxyethers, β-hydroxyamines and β-hydroxyhalo compounds, which are valuable intermediates in pharmaceutical, fine chemical, perfume and agrochemical synthesis. Water wonder: Iridicycle catalysts are versatile and allow the highly efficient and chemoselective transfer hydrogenation of a variety of carbonyl compounds, including problematic and challenging ones, with formate in neat water (see scheme).
Talwar, Dinesh,Wu, Xiaofeng,Saidi, Ourida,Salguero, Noemí Poyatos,Xiao, Jianliang
supporting information
p. 12835 - 12842
(2015/03/30)

Discovery of aromatic components with excellent fragrance properties and biological activities: β-ionols with antimelanogenetic effects and their asymmetric syntheses
Both enantiomers of dihydro-β-ionol and β-ionol, contained in the aromatic components of Osmanthus flower and of Hakuto peach, were obtained with high optical purity by lipase-catalyzed kinetic resolution of the racemates. It was found that all these enantiomers had different characteristic favorable scents and high antimelanogenetic effects. The absolute configuration and the enantiomer ratios of dihydro-β-ionol in the aromatic components of Osmanthus flower and of Hakuto peach were determined. The asymmetric synthesis of (R)-dihydro-β-ionol, one of the most valuable raw materials for fragrance and flavor, was performed from inexpensive β-ionone via lipase-catalyzed dynamic kinetic resolution followed by reduction.
Komaki, Ryoichi,Ikawa, Takashi,Saito, Kozumo,Hattori, Kazuyo,Ishikawa, Natsuyo,Fukawa, Hidemichi,Egi, Masahiro,Akai, Shuji
p. 310 - 314
(2013/05/08)

New heterogeneous B(OEt)3-MCM-41 catalyst for preparation of α,β-unsaturated alcohols
Grafting of boron tri-ethoxide on mesoporous MCM-41 resulted in a highly active catalyst for the Meerwein-Ponndorf-Verley (MPV) reduction and the catalyst denoted as B(OEt)3-MCM-41. Chemoselective reduction of α,β-unsaturated aldehydes and ketones to the corresponding α,β-unsaturated alcohols was achieved by MPV reduction reaction using a new B(OEt)3-MCM-41 catalyst. The prepared new heterogeneous catalyst, B(OEt)3-MCM-41, was characterized in detail by using XRD, 29Si NMR-, 11B NMR-, 13C NMR-, and TEM, N2 adsorption, and ICP-OES. The results demonstrated the successful homogenous distribution of the B(OEt)3 on the MCM-41 support. The heterogeneous B(OEt)3-MCM-41 catalyst, in comparison with the homogeneous B(O i Pr)3 and B(OEt)3 catalysts, displayed similiar catalytic activity in the MPV reduction of α,β-unsaturated aldehydes and ketones with alcohols as reductants. Reduced reaction times and very high selectivities for the unsaturated alcohols were obtained with the heterogenous catalyst compared with the homogeneous catalysts. The B(OEt)3-MCM-41 catalyst was found to be encouraging, as is is recyclable up to six cycles without any significant loss in its catalytic activity.
Uysal, Burcu,Oksal, Birsen S.
p. 3893 - 3911
(2015/06/08)

Reduction of carbonyl compounds to their corresponding of alcohols with [Zn(BH4)2(2-MeOpy)] & [Zn(BH4) 2(2-Mepy)] as new reducing agents (a comparison study)
The reduction of a variety of carbonyl compounds was efficiently carried out with [Zn(BH4)2(2-MeOpy)] and [Zn(BH4) 2(2-Mepy)] as new reducing agents. The reduction reactions were performed to give the corresponding alcohols derivatives in perfect yields.
Khezri, Behrooz,Ghadimi, Farnaz Najaf,Karashi, Chonur Nevisandeh,Setamdideh, Davood
p. 623 - 629
(2013/11/06)

Lanthanide replacement in organic synthesis: Luche-type reduction of α,β-unsaturated ketones in the presence of calcium triflate
Development of a calcium-mediated regioselective 1,2-reduction of challenging α,β-unsaturated ketones, such as 2-cyclopententone, is reported. The corresponding allylic alcohols are obtained in very good regioselectivities using Ca(OTf)2 and NaBH4. Furthermore, we have shown that our method can stereoselectively reduce aziridinyl ketones.
Forkel, Nina V.,Henderson, David A.,Fuchter, Matthew J.
supporting information; scheme or table
p. 2129 - 2132
(2012/09/08)

Mild and efficient reduction of organic carbonyl compounds to their corresponding alcohols with Zn(BH4)2 under protic condition
Zn(BH4)2 (1-2 mmol) in wet THF or CH3CN reduces varieties of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α, β-unsaturated carbonyl compounds to their corresponding alcohols. Reduction reactions were carried out in wet THF at room temperature in high to excellent yields of products. The chemoselective reduction of aldehydes over ketones was accomplished successfully. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was accomplished successfully with this reducing system.
Setamdideh, Davood,Khezri, Behrooz,Rahmatollahzadeh, Mehdi,Poramjad, Avat Ali
experimental part
p. 3591 - 3596
(2012/07/28)

NHC-catalyzed chemo- and regioselective hydrosilylation of carbonyl derivatives
The hydrosilylation of carbonyl derivatives has been explored by the activation of diphenylsilane in the presence of a catalytic amount of an N-heterocyclic carbene (NHC). Presumably, a hypervalent silicon intermediate featuring strong Lewis acid character allows dual activation of both the carbonyl moiety and the hydride at the silicon center. Reduction under mild conditions could be accomplished using this organocatalytic process. Some interesting selectivities have been encountered. Georg Thieme Verlag Stuttgart · New York.
Zhao, Qiwu,Curran, Dennis P.,Malacria, Max,Fensterbank, Louis,Goddard, Jean-Philippe,Lac?te, Emmanuel
supporting information; experimental part
p. 433 - 437
(2012/03/10)

Comparison of heterogeneous B(OiPr)3-MCM-41 and homogeneous B(OiPr)3, B(OEt)3 catalysts for chemoselective MPV reductions of unsaturated aldehydes and ketones
Boron tri-isopropoxide, B(OiPr)3, was immobilized on mesoporous material, MCM-41, and denoted as "B(OiPr) 3-MCM-41". The prepared new heterogeneous catalyst, B(O iPr)3-MCM-41, was characterized in details by using PXRD, FT-IR-, 11B NMR-, 29Si NMR-, 13C NMR-, TEM, EDX, N2 adsorption and ICP-OES. The results demonstrated the successful homogenous distribution of the B(OiPr)3 on the MCM-41 support. Heterogeneous B(OiPr)3-MCM-41 catalyst in comparison with the homogeneous B(OiPr)3 and B(OEt) 3 catalysts, display similiar catalytic activity in the Meerwein-Ponndorf-Verley (MPV) reduction of unsaturated aldehydes and ketones with alcohols as reductants. Reduced reaction times, higher rate constants and very high selectivities for the unsaturated alcohols were obtained with the heterogenous catalyst than the homogeneous catalysts. In most cases, there were no side products other than the desired alcohol. The B(OiPr) 3-MCM-41 catalyst was found to be encouraging as the catalyst is recyclable up to six cycles without any significant loss in its catalytic activity. This work enriches the family of heterogeneous MPV catalysts for chemoselective reductions of unsaturated aldehydes and ketones.
Uysal, Burcu,Oksal, Birsen S.
experimental part
p. 204 - 216
(2012/10/18)

Cyclopentadienyl-NHC iron complexes for solvent-free catalytic hydrosilylation of aldehydes and ketones
Seven cyclopentadienyl-NHC piano-stool iron complexes were prepared and studied in the catalytic hydrosilylation of aldehydes and ketones under visible light irradiation. A significant acceleration of the rate was observed when the reactions were carried out under solvent-free conditions. Single-crystal X-ray structural analyses were performed for complexes 5 and 7. Cp-NHC piano-stool iron complexes were found to be efficient catalysts for the hydrosilylation of aldehydes and ketones under solvent-free conditions and by activation by light irradiation. An acceleration of the rate of the reaction was observed under neat conditions relative to those for the reactions in toluene or THF.
Bezier, David,Jiang, Fan,Roisnel, Thierry,Sortais, Jean-Baptiste,Darcel, Christophe
experimental part
p. 1333 - 1337
(2012/05/20)

Convenient reduction of carbonyl compounds to their corresponding alcohols with NaBH4/(NH4)2C2O4 system
Sodium borohydride (0.4-1.5 equivalents) in the presence of ammonium oxalate (0.2 equivalents) reduces varieties of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α,β- unsaturated carbonyl compounds to their corresponding alcohols. Reduction reactions were carried out in acetonitrile in high to excellent yields of products. The chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was achieved successfully with this reducing system.
Setamdideh, Davood,Ghahremani, Sahar
experimental part
p. 91 - 97
(2012/07/14)

HYDROGENATION OF ESTERS OR CARBONYL GROUPS WITH TETRADENTATE AMINO/IMINO-THIOETHER BASED RUTHENIUM COMPLEXES
The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of specific ruthenium catalysts, or pre-catalysts, in hydrogenation processes for the reduction of ketones and/or aldehydes into the corresponding alcohol respectively. Said catalysts are ruthenium complexes comprising a tetradentate ligand (L4) coordinating the ruthenium with: - two nitrogen atoms, each in the form of a primary or secondary amine (i.e. a NH2 or NH group) or N-alkyl imine functional groups (i.e. a C=N group), and - two sulfur atoms, each in the form of thioether functional groups.
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Page/Page column 21-22

(2012/07/13)

TiO2 as an efficient catalytic surface for reduction of carbonyl compounds with NaBH4 under solvent-free, solid-gel and microwave irradiation
Structurally different carbonyl compounds such as aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones and acyloins were reduced efficiently by NaBH4/TiO2 system under solvent-free, solid-gel and microwave irradiation. The chemoselective reduction of aldehydes over ketones was achieved successfully by NaBH4/TiO 2 system at solvent-free condition. In addition, regioselectivity and exclusive 1,2-reduction of Conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was accomplished successfully with this reducing system.
Setamdideh, Davood,Karimi, Zahra,Rahimi, Fatemeh
experimental part
p. 1621 - 1634
(2012/06/16)

HYDROGENATION OF ESTERS OR CARBONYL GROUPS WITH PHOSPHINO-OXIDE BASED RUTHENIUM COMPLEXES
The present invention relates to the field of catalytic hydrogenation and, more particularly, to the use of specific ruthenium catalysts or pre-catalysts in hydrogenation processes for the reduction of ketones, aldehydes, esters or lactones into their corresponding alcohols or diols respectively. The preferred catalysts are ruthenium complexes comprising a ligand of the type (N—N) type and a ligand of the type (P—PO).
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(2011/08/08)

One-pot synthesis of optically active allyl esters via lipase-vanadium combo catalysis
The combination of vanadium-oxo compounds (3 or 4) with a lipase produced the regio- and enantioconvergent transformation of racemic allyl alcohols (1 or 2) into optically active allyl esters. In this system, the vanadium compounds catalyzed the continuous racemization of the alcohols along with the transposition of the hydroxyl group, while the lipase effected the chemo- and enantioselective esterification to achieve the dynamic kinetic resolution.
Akai, Shuji,Hanada, Ryosuke,Fujiwara, Noboru,Kita, Yasuyuki,Egi, Masahiro
supporting information; experimental part
p. 4900 - 4903
(2011/01/12)

Wet SiO2 as a suitable media for fast and efficient reduction of carbonyl compounds with NABH3CN under solvent-free and acid-free conditions
Reduction of carbonyl compounds such as aldehydes, ketones, α,β-unsaturated enals and enones, α-diketones and acyloins was carried out readily with NaBH3CN in the presence of wet SiO2 as a neutral media. The reactions were performed at solvent-free conditions in oil bath (70-80 °C) or under microwave irradiation (240 W) to give the product alcohols in high to excellent yields. Regioselective 1,2-reduction of conjugated carbonyl compounds took place in a perfect selectivity without any side product formation.
Kouhkan, Mehri,Zeynizadeh, Behzad
experimental part
p. 2961 - 2966
(2012/04/17)

Highly active iridium catalysts for the hydrogenation of ketones and aldehydes
The pressure hydrogenation capabilities of the iridium pincer complexes IrH2Cl[(iPr2PC2H4) 2NH] (1) and IrH3[(iPr2PC 2H4)2NH] (2) are described and compared to related results obtained previously in transfer hydrogenation. Complex 1 was shown to act as a convenient air-stable entry point to the active catalyst 2, in the presence of base and hydrogen gas. The catalysts are active in a range of solvents, including CH2Cl2 and CHCl3, in contrast to related ruthenium systems. This class of iridium complexes is very effective for the direct hydrogenation of a wide range of carbonyl compounds including ketones, diketones, α,β-unsaturated ketones and aldehydes. A catalytic cycle is proposed for this system which involves an ionic heterolytic bifunctional hydrogenation mechanism. This journal is
Chen, Xuanhua,Jia, Wenli,Guo, Rongwei,Graham, Todd W.,Gullons, Meredith A.,Abdur-Rashid, Kamaluddin
experimental part
p. 1407 - 1410
(2009/06/05)

Aminophosphine ligands R2P(CH2)nNH 2 and ruthenium hydrogenation catalysts RuCl2(R 2P(CH2)nNH2)2
The aminophosphine ligands R2P(CH2) 2NH2 and R2P(CH2)3NH 2 (R = Ph, iPr, tBu) were isolated in good to excellent yields from the reaction of LiPR2 with Cl(CH 2)2N(TMS)2 and Cl(CH2) 3N(TMS)2, respectively, followed by hydrolysis. This approach allows fine tuning of the ligands' stereoelectronic properties through the variation of the substituents on the phosphine. The aminophosphine ligands were used to prepare the ruthenium complexes RuCl2(R 2P(CH2)2NH2)2 and RuCl2(R2P(CH2)3NH2) 2 by reacting a 2:1 mixture of the respective ligand and [RuCl 2(cod)]n in an appropriate solvent. The resulting complexes were found to be excellent catalysts for the hydrogenation of ketones and imines. The Royal Society of Chemistry 2009.
Jia, Wenli,Chen, Xuanhua,Guo, Rongwei,Sui-Seng, Christine,Amoroso, Dino,Lough, Alan J.,Abdur-Rashid, Kamaluddin
experimental part
p. 8301 - 8307
(2010/03/04)

IRIDIUM CATALYSTS FOR CATALYTIC HYDROGENATION
The present disclosure relates to a process for the reduction of compounds comprising one or more carbon-oxygen (C═O) double bonds, to provide the corresponding alcohol, comprising contacting the compound with hydrogen gas at a pressure greater than 3 atm and a catalyst comprising an iridium aminodiphosphine complex.
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Page/Page column 6; 8

(2009/01/20)

Applications of lanthanide trichloride hydrates prepared from mischmetall in Luche-type reduction
An inexpensive alloy of light lanthanides, called Mischmetall, has been used in the preparation of a mixture of lanthanide trichloride hydrates. The use of this new type of material is described in Luche-type reductions. Georg Thieme Verlag Stuttgart.
Lannou, Marie-Isabelle,Hélion, Florence,Namy, Jean-Louis
p. 2707 - 2710
(2008/02/12)

Mild and convenient method for reduction of carbonyl compounds with the NaBH4/charcoal system in wet THF
The NaBH4/C (charcoal) system reduces a variety of carbonyl compounds such as aldehydes, ketones, acyloins and α-diketones to their corresponding alcohols in high to excellent yields. Reduction reactions were carried out in wet THF at r.t. In addition, regioselective 1,2-reduction of α,β-unsaturated aldehydes and ketones was achieved perfectly with this reducing system. By decreasing the amount of aprotic solvent, all reductions took place fast and efficiently under solid-gel condition.
Setamdideh, Davood,Zeynizadeh, Behzad
p. 1275 - 1281
(2008/09/18)

Solvent-free reduction of aldehydes and ketones using solid acid-activated sodium borohydride
A simple and convenient procedure for the reduction of aldehydes and ketones with sodium borohydride activated by solid acids such as boric acid, benzoic acid, and p-toluenesulfonic acid monohydrate under solvent-free conditions is described.
Cho, Byung Tae,Kang, Sang Kyu,Kim, Min Sung,Ryu, Soo Ryeon,An, Duk Keun
p. 8164 - 8168
(2007/10/03)

NaBH4/NaHSO4·H2O a heterogeneous acidic system for a mild and convenient reduction of carbonyl compounds under protic condition
NaBH4 in the presence of sodium bisulfate (NaHSO 4·H2O), a weakly acidic reagent, efficiently reduces a variety of carbonyl compounds such as aldehydes, ketones, α, β-unsaturated aldehydes and ketones, α-diketones and acyloins to their corresponding alcohols in acetonitrile under heterogeneous condition. Reduction reactions were accomplished at room temperature or under reflux condition.
Zeynizadeh, Behzad,Behyar, Tarifen
p. 453 - 457
(2007/10/03)

Titanyl acetylacetonate as an efficient catalyst for regioselective 1,2-reduction of α,β-unsaturated carbonyl compounds and conversion of α-diketones & acyloins to vicinal diols with sodium borohydride
α,β-Unsaturated aldehydes and ketones were reduced readily and exclusively to their corresponding allylic alcohols with NaBH4 and catalytic amounts of titanyl acetylacetonate at room temperature. Reduction reactions were carried out in CH3CN or THF. This reducing system was also efficient for the reduction of α-diketones and acyloins to their corresponding vicinal diols in CH3CN.
Zeynizadeh, Behzad
p. 525 - 530
(2007/10/03)

Water as a green solvent for fast and efficient reduction of carbonyl compounds with NaBH4 under microwave irradiation
Reduction of varieties of carbonyl compounds such as aldehydes, ketones, α,β-unsaturated aldehydes and ketones, α-diketones and acyloins was carried out very fast and efficiently by sodium borohydride in water under microwave irradiation. The corresponding product alcohols were obtained in high to excellent yields.
Zeynizadeh, Behzad,Setamdideh, Davood
p. 1179 - 1184
(2007/10/03)

Wet THF as a suitable solvent for a mild and convenient reduction of carbonyl compounds with NaBH4
NaBH4 in wet THF can readily reduce varieties of carbonyl compounds such as aldehydes, ketones, conjugated enones, acyloins, and α-diketones to their corresponding alcohols in good to excellent yields. Reduction reactions were performed at room temperature or under reflux condition. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system.
Zeynizadeh, Behzad,Behyar, Tarifeh
p. 307 - 315
(2007/10/03)

Reducing ability of supramolecular C60 dianion toward C=O, C=C and N-N bonds
Different from C60 dianion which readily reacts with electrophiles, supramolecular C60 dianion (2) generated from γ-cyclodextrin-bicapped C60 (1) and NaBH4 (or diborate) in DMSO-H2O (9:1, v/v) is able to reduce N-N+, C=C-EWG and C=O bonds to provide the respective dihydro derivatives; 1-mediated reduction of acetophenone with NaBH4 in the presence of (Me 2N)2CH2 and EtONa gives turn over frequency (TOF)/h of 400. The Royal Society of Chemistry 2005.
Takekuma, Shin-Ichi,Takekuma, Hideko,Yoshida, Zen-Ichi
p. 1628 - 1630
(2007/10/03)

Direct and indirect reductive amination of aldehydes and ketones with solid acid-activated sodium borohydride under solvent-free conditions
A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride activated by boric acid, p-toluenesulfonic acid monohydrate or benzoic acid as reducing agent under solvent-free conditions is described.
Byung, Tae Cho,Sang, Kyu Kang
p. 5725 - 5734
(2007/10/03)

Ultrasound-promoted reduction of conjugated enones, α-diketones and acyloins with NaBH4 under aprotic condition
A variety of conjugated enones are reduced regioselectively to their corresponding allylic alcohols with NaBH4 under ultrasound irradiation. Reduction reactions were performed in THF at room temperature and the product alcohols were obtained in high to excellent yields. This system is also efficient for the reduction of α-diketones and acyloins to vicinal diols.
Zeynizadeh, Behzad,Yahyaei, Saiedeh
p. 699 - 703
(2007/10/03)

Chemoselective Reduction of Complex α,β-Unsaturated Ketones to Allylic Alcohols over Ir-Metal Particles on β Zeolites
The combination of Ir, which has a strong affinity for carbonyl groups, with an acid H-β zeolite as a support and promotor, provides an effective catalyst for the chemoselective hydrogenation of α,β-unsaturated aldehydes and ketones to the corresponding allylic alcohols. Steroidal enones are suitable substrates for this transformation (see scheme). R = CH (Me)(CH2)3CH(Me)2.
De Bruyn, Mario,Coman, Simona,Bota, Roxana,Parvulescu, Vasile I.,De Vos, Dirk E.,Jacobs, Pierre A.
p. 5333 - 5336
(2007/10/03)

Modified hydroborate agent: (2,2′-bipyridyl)(tetrahydroborato)zinc complex, [Zn(BH4)2(bpy)], as a new, stable, efficient ligand-metal hydroborate and chemoselective reducing agent
(2,2′-Bipyridyl)(tetrahydroborato)zinc complex, [Zn(BH4)2(bpy)], is a new white stable compound which has been used for efficient reduction of variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α, β-unsaturated carbonyl compounds (1,2-reduction) to their corresponding alcohols in acetonitrile at room temperature. Excellent chemoselectivity was also observed for the reduction of aldehydes over ketones with this reducing agent.
Zeynizadeh, Behzad
p. 317 - 326
(2007/10/03)

Hydrogenation versus Transfer Hydrogenation of Ketones: Two Established Ruthenium Systems Catalyze Both
The established standard ketone hydrogenation (abbreviated HY herein) precatalyst [Ru(Cl)2((S)-tolbi-nap){(S,S)-dpen}] ((S),(S,S)-1) has turned out also to be a precatalyst for ketone transfer hydrogenation (abbreviated TRHY herein) as tested on the substrate acetophenone (3) in iPrOH under standard conditions (45°C, 45 bar H2 or Ar at atmospheric pressure). HY works at a substrate catalyst ratio (s:c) of up to 106 and TRHY at s:c4. Both produce (R)-1-phenylethan-1-ol ((R)-4), but the ee in HY are much higher (78-83%) than in TRHY (4-62%). In both modes, iPrOK is needed to generate the active catalysts, and the more there is (1-4500 equiv), the faster the catalytic reactions. The ee is about constant in HY and diminishes in TRHY as more iPrOK is added. The ketone TRHY precatalyst [Ru(Cl)2((S,S)-cyP2(NH)2)] ((S,S)-2), established at s:c=200, has also turned out to be a ketone HY precatalyst at up to s:c=106, again as tested on 3 in iPrOH under standard conditions. The enantioselectivity is opposite in the two modes and only high in TRHY: with (S,S)-2, one obtains (R)-4 in up to 98% ee in TRHY as reported and (S)-4 in 20-25% ee in HY. iPrOK is again required to generate the active catalysts in both modes, and again, the more there is, the faster the catalytic reactions. The ee in TRHY are only high when 0.5-1 equivalents iPrOK are used and diminish when more is added, while the (low) ee is again about constant in HY as more iPrOK is added (0-4500 equiv). The new [Ru(H)(Cl)((S,S)-cyP2(NH) 2)] isomers (S,S)-9A and (S,S)-9B (mixture, exact structures unknown) are also precatalysts for the TRHY and HY of 3 under the same conditions, and (R)-4 is again produced in TRHY and (S)-4 in HY, but the lower ee shows that in TRHY (S,S)-9A/(S,S)-9B do not lead to the same catalysts as (S,S)-2. In contrast, the ee are in accord with (S,S)-9A/(S,S)-9B leading to the same catalysts as (S,S)-2 in HY. The kinetic rate law for the HY of 3 in iPrOH and in benzene using (S,S)-9A/(S,S)-9B/iPrOK or (S,S)-9A/(S,S)-9B/tBuOK is consistent with a fast, reversible addition of 3 to a five-coordinate amidohydride (S,S)-11 to give an (S,S)-11-substrate complex, in competition with the rate-determining addition of H2 to (S,S)-11 to give a dihydride [Ru(H)2((S,S)-cyP2(NH)2)] (S,S)-10, which in turn reacts rapidly with 3 to generate (S)-4 and (S,S)-11. The established achiral ketone TRHY precatalyst [Ru(Cl)2(ethP 2(NH)2)] (12) has turned out to be also a powerful precatalyst for the HY of 3 in iPrOH at s:c=106 and of some other substrates. Response to the presence of iPrOK is as before, except that 12 already functions well without it at up to s:c=106.
Rautenstrauch, Valentin,Hoang-Cong, Xuan,Churlaud, Raphael,Abdur-Rashid, Kamaluddin,Morris, Robert H.
p. 4954 - 4967
(2007/10/03)

Chemoselective Hydrogen Transfer Reduction of Unsaturated Ketones to Allylic Alcohols with Solid Zr and Hf Catalysts
α,β-Unsaturated ketones were reduced to allylic alcohols with high chemo- and diastereoselectivity, using Zr and Hf compounds heterogenised on mesoporous molecular sieves.
De Bruyn, Mario,De Vos, Dirk E.,Jacobs, Pierre A.
p. 1120 - 1125
(2007/10/03)

Phosphine effects in the copper(I) hydride-catalyzed hydrogenation of ketones and regioselective 1,2-reduction of α,β-unsaturated ketones and aldehydes. Hydrogenation of decalin and steroidal ketones and enones
The stereoselectivity and regioselectivity of the catalytic hydrogenation of ketones and α,β-unsaturated ketones and aldehydes using soluble copper(I) hydride catalysts have been investigated as a function of the ancillary phosphine ligand. While a relatively narrow range of aryldialkylphosphine ligands produce active hydrogenation catalysts, some ligands provide higher selectivity for 1,2-reduction of acyclic unsaturated carbonyl substrates than observed using the previously reported dimethylphenylphosphine-stabilized catalyst. The synthetic utility of this class of hydridic hydrogenation catalysts is illustrated by the hydrogenation of decalin and steroidal ketones and enones, the latter giving allylic alcohols with high selectivity. (C) 2000 Elsevier Science Ltd.
Chen, Jian-Xin,Daeuble, John F.,Stryker, Jeffrey M.
p. 2789 - 2798
(2007/10/03)

Highly chemoselective catalytic hydrogenation of unsaturated ketones and aldehydes to unsaturated alcohols using phosphine-stabilized copper(I) hydride complexes
A base metal hydrogenation catalyst composed of the phenyldimethylphosphine-stabilized copper(I) hydride complex provides for the highly chemoselective hydrogenation of unsaturated ketones and aldehydes to unsaturated alcohols, including the regioselective 1,2-reduction of α,β- unsaturated ketones and aldehydes to allylic alcohols. The active catalyst can be derived in situ by phosphine exchange using commercial [(Ph3P)CuH]6 or from the reaction of copper(l) chloride, sodium tert-butoxide, and dimethylphenylphosphine under hydrogen. The catalyst derived from 1,1,1- tris(diphenylphosphinomethyl)ethane is mechanistically interesting but less synthetically useful. (C) 2000 Elsevier Science Ltd.
Chen, Jian-Xin,Daeuble, John F.,Brestensky, Donna M.,Stryker, Jeffrey M.
p. 2153 - 2166
(2007/10/03)