- Reaction of ethyl 2,2-dimethoxycyclopropanecarboxylates with m-CPBA. Discovery of two new related degradative processes leading to β-hydroxyacid derivatives
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The reaction of the 3-alkyl-substituted and 3,3-dialkyl-substituted ethyl 2,2-dimethoxycyclopropanecarboxylates 1-3 with m-CPBA in CH2Cl2 leads to the formation of the β-hydroxyacid derivatives 4-6 via two related processes involving the scission of both the C1-C2 and C2-C3 bonds and consequently to the degradation of the original cyclopropane carbon skeleton (extrusion of the C-2 carbon). Cis- and trans-2-ethoxycyclopropanecarboxylic acid ethyl esters 9 and 10, respectively, structurally related to 1-3, are unreactive under the same conditions. A hypothesis explaining the observed reactivity is formulated.
- Piccialli, Vincenzo,Graziano, M. Liliana
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Read Online
- SYNERGISM OF HYDROGENATING CAPACITY IN THE Ni-Pd/Al2O3 SYSTEM
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In liquid-phase hydrogenation of ethyl acetoacetonate on bimetallic Ni-Pd catalysts supported on Al2O3, the reaction rate increases sharply and passes through a maximum with an increase in the concentration of Pd.The change in the rate of hydrogenation with a change in the composition of the catalysts is not due to a change in the dispersion of the metallic phase in the them or enrichment of their surface with one of the metals.
- Vedenyapin, A. A.,Giorgadze, N. G.,Murina, I. P.,Yushin, S. V.,Chivadze, G. O.,et al.
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Read Online
- Effect of the conditions of preparation of asymmetric LaNi3Co2Hn catalysts on their hydrogenating and enantioselective properties
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1. The conditions of modification (temperature, concentration of R, R-(+)-tartaric acid, solvent) affect the asymmetric properties of tartrate complexes of LaNi3Co2Hn hydrides. 2. The combined effect of NaBr (as a comodifier) and trimethylacetic acid (as a promoter) on the optical yield of the reaction was established.
- Starodubtseva,Konenko,Fedorovskaya,Klabunovskii,Mordovin
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Read Online
- Synthesis, Structure, and Catalytic Hydrogenation Activity of [NO]-Chelate Half-Sandwich Iridium Complexes with Schiff Base Ligands
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A series of N,O-coordinate iridium(III) complexes with a half-sandwich motif bearing Schiff base ligands for catalytic hydrogenation of nitro and carbonyl substrates have been synthesized. All iridium complexes showed efficient catalytic activity for the hydrogenation of ketones, aldehydes, and nitro-containing compounds using clean H2 as reducing reagent. The iridium catalyst displayed the highest TON values of 960 and 950 in the hydrogenation of carbonyl and nitro substrates, respectively. Various types of substrates with different substituted groups afforded corresponding products in excellent yields. All N,O-coordinate iridium(III) complexes 1-4 were well characterized by IR, NMR, HRMS, and elemental analysis. The molecular structure of complex 1 was further characterized by single-crystal X-ray determination.
- Lv, Wen-Rui,Li, Rong-Jian,Liu, Zhen-Jiang,Jin, Yan,Yao, Zi-Jian
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p. 8181 - 8188
(2021/05/26)
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- Coupling Droplet Microfluidics with Ion Mobility Spectrometry for Monitoring Chemical Conversions at Nanoliter Scale
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We introduce the coupling of droplet microfluidics and ion mobility spectrometry (IMS) to address the challenges of label-free and chemical-specific detection of compounds in individual droplets. In analogy to the established use of mass spectrometry, droplet-IMS coupling can be also achieved via electrospray ionization but with significantly less instrumental effort. Because IMS instruments do not require high-vacuum systems, they are very compact, cost-effective, and robust, making them an ideal candidate as a chemical-specific end-of-line detector for segmented flow experiments. Herein, we demonstrate the successful coupling of droplet microfluidics with a custom-built high-resolution drift tube IMS system for monitoring chemical reactions in nL-sized droplets in an oil phase. The analytes contained in each droplet were assigned according to their characteristic ion mobility with limit of detections down to 200 nM to 1 μM and droplet frequencies ranging from 0.1 to 0.5 Hz. Using a custom sheath flow electrospray interface, we have further achieved the chemical-specific monitoring of a biochemical transformation catalyzed by a few hundred yeast cells, at single droplet level.
- Hartner, Nora T.,Wink, Konstantin,Raddatz, Christian-Robert,Thoben, Christian,Schirmer, Martin,Zimmermann, Stefan,Belder, Detlev
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p. 13615 - 13623
(2021/10/21)
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- Concise Synthesis of (+)-[13C4]-Anatoxin-a by Dynamic Kinetic Resolution of a Cyclic Iminium Ion
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An asymmetric total synthesis of [13C4]-anatoxin-a ([13C4]-1) has been developed from commercially available ethyl [13C4]-acetoacetate ([13C4]-15). The unique requirements associated with isotope incorporation inspired a new, robust, and highly scalable route, providing access to 0.110 g of this internal standard for use in the detection and precise quantification of anatoxin-a in freshwater. A highlight of the synthesis is a method that leverages a cyclic iminium ion racemization to achieve dynamic kinetic resolution in an enantioselective Morita–Baylis–Hillman (MBH) cyclization.
- Chen, Karen Y.,Lacharity, Jacob J.,Mailyan, Artur K.,Zakarian, Armen
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supporting information
p. 11364 - 11368
(2020/05/18)
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- Cobalt-Catalyzed Alkoxycarbonylation of Epoxides to β-Hydroxyesters
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Herein, we developed a new and practical catalytic system for the carbonylative synthesis of β-hydroxyesters. By using simple, cheap, and air-stable cobalt(II) bromide as the catalyst, combined with pyrazole and catalytic amount of manganese, active cobalt complex can be generated in situ and can catalyze various epoxides to give the corresponding β-hydroxyesters in moderate to excellent yields. Mechanism studies indicate that pyrazole plays a crucial role in this reaction. Moreover, with the addition of the catalytic amount of manganese, the active cobalt catalyst can be regenerated, which provides a possibility for reusing the cobalt catalyst.
- Xu, Jian-Xing,Wu, Xiao-Feng
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p. 9907 - 9912
(2019/08/26)
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- Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst
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A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H2 as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.
- Yao, Zi-Jian,Zhu, Jing-Wei,Lin, Nan,Qiao, Xin-Chao,Deng, Wei
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p. 7158 - 7166
(2019/06/13)
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- Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
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A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10:000 in most cases; S/C = 50:000 or 100:000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26:000 mol mol-1 h-1. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.
- Liu, Ji-Tian,Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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supporting information
p. 2118 - 2124
(2018/05/24)
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- Ruthenium(II) Complexes of 4′-(Aryl)-2,2′:6′,2′′-terpyridyl Ligands as Simple Catalysts for the Transfer Hydrogenation of Ketones
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A series of cationic [Ru(L)(PPh3)2Cl]+ (1–3) and neutral [Ru(L)(PPh3)Cl2] (4–6) RuII complexes were synthesized by reacting [RuCl2(PPh3)2] with 4′-(aryl)-2,2′:6′,2′′-terpyridyl-based ligands (L1–L3) with various aryl groups (tolyl, phenyl and 4-fluorophenyl). The synthesized RuII complexes were unambiguously characterized by various spectroscopic techniques such as FTIR and multinuclear NMR spectroscopy as well as HRMS. The neutral complexes (4–6) were also structurally characterized by single-crystal X-ray diffraction studies. Photophysical and electrochemical studies of the RuII complexes were performed to elucidate the effects of the 4′-aryl substituents of L1–L3. These RuII complexes show good catalytic activities in the transfer hydrogenation (TH) of ketones with a wide substrates scope in 2-propanol under reflux. An optimization study revealed that the neutral RuII complexes are better catalysts than the cationic RuII complexes for TH reactions. Finally, [Ru(L1)(PPh3)2H]+ (7) with a [RuII–H] functionality was successfully synthesized and isolated and is proposed as the catalytically active species. A control experiment with the [RuII–H] complex in the absence of base was performed to establish the mechanism for the catalytic TH of ketones.
- Maity, Apurba,Sil, Amit,Patra, Sanjib K.
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p. 4063 - 4073
(2018/09/11)
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- Synthesis and Catalytic Activity of (3,4-Diphenylcyclopentadienone)Iron Tricarbonyl Compounds in Transfer Hydrogenations and Dehydrogenations
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Four (3,4-diphenylcyclopentadienone)iron tricarbonyl compounds were synthesized, and their activities in transfer hydrogenations of carbonyl compounds and transfer dehydrogenations of alcohols were explored and compared to those of the well-established [2,5-(SiMe3)2-3,4-(CH2)4(η4-C4C=O)]Fe(CO)3 (3). A new compound, [2,5-bis(3,5-dimethylphenyl)-3,4-diphenylcyclopentadienone]iron tricarbonyl (7), was the most active catalyst in both transfer hydrogenations and dehydrogenations, and compound 3 was the least active catalyst in transfer hydrogenations. Evidence was found for product inhibition of both 3 and 7 in a transfer dehydrogenation reaction, with the activity of 3 being more heavily affected. A monomeric iron hydride derived from 7 was spectroscopically observed during a transfer hydrogenation, and no diiron bridging hydrides were found under reductive or oxidative conditions. Initial results in the transfer hydrogenation of N-benzylideneaniline showed that 3 was a significantly less active catalyst in comparison to the (3,4-diphenylcyclopentadienone)iron tricarbonyl compounds.
- Funk, Timothy W.,Mahoney, Andrew R.,Sponenburg, Rebecca A.,Zimmerman, Kathryn P.,Kim, Daniel K.,Harrison, Emily E.
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supporting information
p. 1133 - 1140
(2018/04/17)
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- Cobalt carbonyl ionic liquids based on the 1,1,3,3-tetra-alkylguanidine cation: Novel, highly efficient, and reusable catalysts for the carbonylation of epoxides
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A series of novel cobalt carbonyl ionic liquids based on 1,1,3,3-tetra-alkyl-guanidine, such as [1,1-dimethyl-3,3-diethylguanidinium][Co(CO)4] (3a), [1,1-dimethyl-3,3-dibutylguanidinium][Co(CO)4] (3b), [1,1-dimethyl-3,3-tetramethyleneguanidinium][Co(CO)4] (3c), and [1,1-dimethyl-3,3-pentamethyleneguanidinium] [Co(CO)4] (3d), were synthesized in good yields and were also characterized using infrared spectroscopy, ultraviolet-visible spectroscopy, 1H nuclear magnetic resonance (NMR) spectroscopy, 13C NMR spectroscopy, high–resolution mass spectrometry, differential scanning calorimetry, and thermogravimetric analysis. The four compounds exhibited high thermal and chemical stability. In addition, the catalytic performance of these compounds was investigated in the carbonylation of epoxides, with 3a exhibiting the best catalytic activity without the aid of a base as the additive. The catalyst could be reused at least six times without significant decreases of the selectivity or conversion rate. Moreover, the catalyst system exhibited good tolerance with terminal epoxides bearing alkyl, alkenyl, aryl, alkoxy, and chloromethyl functional groups.
- Zhang, Wei,Han, Feng,Tong, Jin,Xia, Chungu,Liu, Jianhua
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p. 805 - 812
(2017/05/29)
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- 1,1,3,3-tetra alkyl guanidine carbonyl cobalt metal organic ion liquid and preparation method and application thereof
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The invention discloses a 1,1,3,3-tetra alkyl guanidine carbonyl cobalt metal organic ion liquid. A structure formula of the ion liquid is shown in the description. The invention also discloses a preparation method of the ion liquid and application of the ion liquid in synthesizing of 3-hydroxy carboxylate by epoxy compound hydroesterification. The 1,1,3,3-tetra alkyl guanidine carbonyl cobalt metal organic ion liquid has the advantages that guanidine cation has the double functions of stabilizing tetra carbonyl cobalt cation and using as a Lewis acid to activate epoxy compound primer; compared with the traditional Co2(CO)8/azacycle catalytic system, the use of a nitrogen-containing organic matter is avoided; the ion liquid can be recycled and repeatedly used, the use rate of carbonyl cobalt is improved, and the production cost is reduced; the stability of the 1,1,3,3-tetra alkyl guanidine carbonyl cobalt metal organic ion liquid is high, the ion liquid can be repeatedly applied to catalysis of epoxy compound hydroesterification for multiple times, the catalytic reaction effect is good, and the separation and recycling are convenient.
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Paragraph 0038-0053
(2017/08/31)
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- An efficient FeCl3-mediated approach for reduction of ketones through N-heterocyclic carbene boranes
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An efficient FeCl3-mediated approach for reduction of ketones by NHC-BH3 has been developed. A series of ketones were smoothly converted to the corresponding alcohols in good to excellent yields through NHC-BH3 reductive process.
- Wang, Ming-Hui,Chen, Ling-Yan
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supporting information
p. 732 - 735
(2017/03/31)
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- Zinc-Mediated Efficient and Selective Reduction of Carbonyl Compounds
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We herein describe for the first time that an optimized combination of Zn and NH4Cl can be used for the selective reduction of aldehydes and ketones to the corresponding alcohols. The aldehyde and keto groups are selectively reduced in the presence of azide, cyano, epoxy, ester, and carbon–carbon double-bond functional groups. A broad functional-group compatibility, chemoselective reduction of aldehydes in the presence of ketones, and selective reduction of isatins at the C3 carbonyl group are the highlights of the present method.
- Mandal, Tirtha,Jana, Snehasish,Dash, Jyotirmayee
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p. 4972 - 4983
(2017/09/13)
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- Synthesis of an advanced intermediate enroute to thiomarinol antibiotics
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A stereoselective synthesis of the C1-C14 fragment of thiomarinols is disclosed. The key steps include the stereoselective preparation of an allylic sulfide via a chloro sulfide by 1,2-asymmetric induction, ring-closing metathesis reaction, Kirmse-Doyle reaction for the preparation of a γ,δ-unsaturated ester, Nozaki-Hiyama-Kishi coupling and Julia-Kocienski olefination reaction. Substrate controlled asymmetric induction has been advantageously employed for the creation of stereogenic centers. Noyori transfer hydrogenation and asymmetric hydrogenation reactions have been utilized for the creation of carbinol stereocenters.
- Raghavan, Sadagopan,Ravi, Anil
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p. 2814 - 2823
(2017/04/14)
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- Immobilization of Carbonylcobalt Catalyst by Poly(4-vinylpyridine) (P4VP) through N→Co Coordination Bonds: The Promotional Effect of Pyridine and the Reusability of Polymer Catalyst
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A carbonylcobalt catalyst, immobilized by poly(4-vinylpyridine) (P4VP) through N→Co coordination bonds, has been prepared by solvothermal method. It has been revealed that the pyridine fragments in the polymer catalyst act not only as promoters to improve the catalytic performance of the carbonylcobalt catalyst for alkoxycarbonylation of ethylene oxide to methyl 3-hydroxypropanoate but also as stabilizers to enhance the reusability of the polymer catalyst. Furthermore, the polymer catalyst could be easily separated by filtration and reused with only a slight loss of catalytic efficiency.
- Liu, Yu-Bing,Wang, Yi-Ning,Lu, Hai-Meng,Liang, Shuang,Xu, Bo-Lian,Fan, Yi-Ning
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supporting information
p. 3159 - 3164
(2016/11/29)
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- Base-Free Transfer Hydrogenation of Ketones Using Cp?Ir(pyridinesulfonamide)Cl Precatalysts
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N-(2-(Pyridin-2-yl)ethyl)benzenesulfonamide derivatives and 1,1,1-trifluoro-N-(2-(pyridin-2-yl)ethyl)methanesulfonamide (1-4), along with three-legged piano stool Cp?IrIIICl complexes (5-11) (Cp? = pentamethylcyclopentadienyl) bearing pyridinesulfonamide ligands with varying electronic parameters, were synthesized. These ligands and air-stable complexes were characterized by 1H and 13C{1H} NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Precatalysts, 5-11, were assessed for transfer hydrogenation of aryl, diaryl, dialkyl, linear, cycloaliphatic, and α,β-unsaturated ketones, diones, β-ketoesters, and a biomass-derived substrate with 2-propanol, using 1 mol % precatalyst. Catalysis was also efficient using a 0.1 mol % loading. Remarkably, all catalysis experiments can be conducted in air without dried and degassed substrates, and basic additives and halide abstractors are not required for high activity in transfer hydrogenation. Control experiments and a mercury poisoning experiment support a homogeneous catalyzed pathway. Overall, the fastest reactions are observed using electron-poor substrates and precatalysts bearing electron-rich ligands.
- Ruff, Andrew,Kirby, Christopher,Chan, Benny C.,O'Connor, Abby R.
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p. 327 - 335
(2016/02/19)
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- PROCESS FOR ACYL-TRANSFER ENZYME REACTIONS WITH ACYL- COENZYME A
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The present invention relates to a method for acyltransferase reaction in which an acyl group of acyl coenzyme A is transferred to an acyl group receptor characterized in that the reaction is carried out by production and/or reproduction of acyl coenzyme A from coenzyme A in a reaction system by a chemical thioester exchange reaction with acylthioester. The present invention, wherein expensive acyl CoA is reproduced nonenzymatically in a reaction system, enables to continuously carry out acyltransferase reaction only by putting a small amount of acyl CoA with a donor and a receptor of an acyl group into a system. Accordingly, the method of the present invention can be applied to an industrial production method of various kinds of compounds including useful biological molecules and synthesis of polymers such as polyester.
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Paragraph 0090
(2016/07/27)
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- The effect of particle size and ligand configuration on the asymmetric catalytic properties of proline-functionalized Pt-nanoparticles
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The effect of particle size on the asymmetric catalytic properties of supported ligand-functionalized nanoparticles (NPs) was investigated for the first time and found to alter significantly the activity but surprisingly not the stereoselectivity. These results suggest that the stereoselectivity of these complex systems is primarily determined by the ligand-reactant interaction, whereas the activity is determined by the particle size.
- Schrader, Imke,Neumann, Sarah,Himstedt, Rieke,Zana, Alessandro,Warneke, Jonas,Kunz, Sebastian
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supporting information
p. 16221 - 16224
(2015/11/16)
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- New Route to Stabilize Ruthenium Nanoparticles with Non-Isolable Chiral N-Heterocyclic Carbenes
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Ru nanoparticles (RuNPs) stabilized by non-isolable chiral N-heterocyclic carbenes (NHCs), namely SIDPhNp ((4S,5S)-1,3-di(naphthalen-1-yl)-4,5-diphenylimidazolidine) and SIPhOH ((S)-3-((1S,2R)-2-hydroxy-1,2-diphenylethyl)-1-((R)-2-hydroxy-1,2-diphenylethyl)-4,5-dihydro-3H-imidazoline), have been synthesized through a new procedure that does not require isolation of the free carbenes. The obtained RuNPs have been characterized by state-of-the-art techniques and their surface chemistry has been investigated by FTIR and solid-state MAS NMR upon the coordination of CO, which indicated the presence of free and reactive Ru sites. Their catalytic activity has been tested in various hydrogenation reactions involving competition between different sites, whereby interesting differences in selectivity were observed, but no enantioselectivity.
- Martnez-Prieto, Luis Miguel,Ferry, Anglique,Lara, Patricia,Richter, Christian,Philippot, Karine,Glorius, Frank,Chaudret, Bruno
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p. 17495 - 17502
(2016/01/25)
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- Whole-cell biocatalysis in deep-eutectic-solvents/aqueous mixtures
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Whole-cell biocatalysis with the use of baker's yeast is demonstrated in different mixtures of water with deep eutectic solvents (DESs; choline chloride/glycerol, 1:2 mol/mol). Enantioselective ketone reduction is observed for long reaction times (>200 h), which suggests that the whole cells remain stable in these neoteric solvents. By changing the proportion of the DES added, a complete inversion of enantioselectivity is observed, from approximately 95 % enantiomeric excess (ee) (S) in pure water to approximately 95 % ee (R) in the pure DES. Presumably, some (S)-oxidoreductases present in baker's yeast are inhibited by DESs. DESpicably good: Whole-cell biocatalysis with the use of baker's yeast is demonstrated in different mixtures of water with deep eutectic solvents (DESs). Enantioselective ketone reduction is observed for long reaction times (>200 h), which suggests that the whole cells remain stable in these neoteric solvents. By changing the proportion of the DES added, a complete inversion of enantioselectivity is observed.
- Maugeri, Zaira,Dominguez De Maria, Pablo
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p. 1535 - 1537
(2014/06/24)
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- Synthesis and Suzuki-Miyaura cross-coupling of enantioenriched secondary potassium β-trifluoroboratoamides: Catalytic, asymmetric conjugate addition of bisboronic acid and tetrakis(dimethylamino)diboron to α,β- unsaturated carbonyl compounds
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Enantioenriched potassium β-trifluoroboratoamides have been synthesized via an asymmetric, copper-catalyzed 1,4-addition of tetrahydroxydiboron (BBA) and tetrakis(dimethylamino)-diboron to α,β-Unsaturated amides. These dibora reagents provide access to the desired organotri-fluoroborates using effective and atom economical sources of boron. The copper-catalyzed β-boration is extended to α,β- Unsaturated ketones and esters. The desired potassium organotrifluoroborates are synthesized with yields up to 92% and enantiomeric ratios up to 98:2. The enantioenriched potassium btrifluoroboratoamides are successfully cross-coupled with an array of aryl and heteroaryl chlorides in high yield with complete stereochemical fidelity as the transmetalation proceeds through an SE2 mechanism via an open transition state.
- Molander, Gary A.,Wisniewski, Steven R.,Hosseini-Sarvaria, Mona
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p. 3037 - 3057
(2014/03/21)
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- Chiral copper(II)-catalyzed enantioselective boron conjugate additions to α,β-unsaturated carbonyl compounds in water
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Copper pins on the boron: The enantioselective 1,4-addition of diboron to α,β-unsaturated compounds proceeds smoothly in the presence of catalytic amounts of Cu(OH)2 and chiral 2,2′-bipyridine ligand in water. A wide substrate scope of α,β-unsaturated carbonyl compounds, including acyclic, cyclic, and β,β-disubstituted enones, α,β-unsaturated esters, amides, and a nitrile, has been shown. Copyright
- Kobayashi, Shu,Xu, Pengyu,Endo, Toshimitsu,Ueno, Masaharu,Kitanosono, Taku
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supporting information
p. 12763 - 12766
(2013/02/22)
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- Selective reduction of ketones using water as a hydrogen source under high hydrostatic pressure
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A selective reduction of a broad variety of ketones is described. The method is based on the combination of a Ni-Al alloy and high hydrostatic pressure (HHP, 2.8 kbar) in an aqueous medium. The reaction of the Ni-Al alloy with water provides in situ hydrogen generation and the high pressure ensures that the H2 formed remains in the solution, thus the CO reduction readily occurs. The application of the HHP resulted in selective formation of the desired products and the common problem of non-selective overhydrogenation could be avoided. In most cases the reductions resulted in high yields and excellent selectivities without the use of any base.
- Tomin, Anna,Lazarev, Alexander,Bere, Matthew P.,Redjeb, Hana,T?r?k, Béla
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experimental part
p. 7321 - 7326
(2012/09/22)
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- Ruthenium-catalyzed asymmetric hydrogenation of 3-oxoglutaric acid derivatives: A study of unconventional solvent and substituent effects
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A series of 3-oxoglutaric acid derivatives have been hydrogenated in different solvents in the presence of [RuCl(benzene)(S)-SunPhos]Cl (SunPhos=(2,2,2′,2′-tetramethyl-[4,4′-bibenzo[d][1,3]dioxole] -5,5′-diyl)bis(diphenylphosphine)). Unlike simple β-keto acid derivatives, these advanced analogues can be readily hydrogenated in uncommon solvents such as THF, CH2Cl2, acetone, and dioxane with high enantioselectivities. Two possible catalytic cycles have been proposed to explain the different reactivities of these 1,3,5-tricarbonyl substrates in the tested solvents. The C-2 and C-4 substituents had notable but irregular influence on the reactivity and enantioselectivity of the reactions. More pronounced solvent effects were observed: the ee values increased from around 20 % in EtOH or THF to 90 % in acetone. Inversion of the product configuration was observed when the solvent was changed from EtOH to THF or acetone, and a mixed solvent system can lead to better enantioselectivity than a single solvent. Pronounced solvent effects: 3-Oxoglutaric acid derivatives have been hydrogenated in various solvents with high enantioselectivities (see scheme). Inversions of the product configuration were observed when the solvent was changed. Mixed solvent systems can give better enantioselectivities than a single solvent.
- Li, Wanfang,Tao, Xiaoming,Ma, Xin,Fan, Weizheng,Li, Xiaoming,Zhao, Mengmeng,Xie, Xiaomin,Zhang, Zhaoguo
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p. 16531 - 16539
(2013/02/22)
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- Ru-catalyzed asymmetric hydrogenation of 3-oxoglutaric acid derivatives via solvent-assisted pinpoint recognition of carbonyls in close chemical propinquity
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Upon comparison of hydrogenation rates of various β-ketocarboxylic acid derivatives, β-ketoamides were found to be hydrogenated slightly faster than β-ketoesters in EtOH in the presence of [RuCl(benzene)(S)- SunPhos]Cl at 70 °C with 20 bar of hydrogen. In THF these differences were so sharpened that β-ketoamides were hydrogenated even faster than in EtOH while the esters were extremely slow. Based on these findings, a series of 3-oxoglutaric acid derived with ester and amide moieties on the two ends were hydrogenated to 3-hydroxyl products with high enantioselectivities.
- Li, Wanfang,Ma, Xin,Fan, Weizheng,Tao, Xiaoming,Li, Xiaoming,Xie, Xiaomin,Zhang, Zhaoguo
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scheme or table
p. 3876 - 3879
(2011/10/01)
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- Ni and Pd mediate asymmetric organoboron synthesis with ester functionality at the β-position
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Catalytic systems based on Ni and Pd complexes modified with chiral P-P ligands can be used in a convenient strategy for enantioselectively adding a boron unit to the β-position of α,β-unsaturated esters.
- Lillo, Vanesa,Geier, Michael J.,Westcott, Stephen A.,Fernandez, Elena
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supporting information; experimental part
p. 4674 - 4676
(2009/12/08)
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- A simple and highly effective method for hydrogenation of arenes by [Rh(COD)Cl]2
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Hydrogenation of arenes, including chiral BINOLs and the lignin model compounds, has been achieved efficiently by using the simple complex [Rh(COD)Cl]2 as catalyst precursor.
- Wang, Da-Wei,Lu, Sheng-Mei,Zhou, Yong-Gui
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supporting information; experimental part
p. 1282 - 1285
(2009/09/06)
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- METHOD FOR SYNTHESIS OF KETO ACID OR AMINO ACID BY HYDRATION OF ACETHYLENE COMPOUND
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An object of the present invention is to provide a method for synthesis of keto acids by hydration of an acetylene compound (acetylene-carboxylic acids) under mild conditions free from harmful mercury catalysts and a method for synthesis of amino acids from acetylene-carboxylic acids in a single container (one-pot or tandem synthesis). In one embodiment of the method according to the present invention for synthesis of keto acids, acetylene-carboxylic acids is hydrated in the presence of a metal salt represented by General Formula (1), where M1 represents an element in Group VIII, IX, or X of the periodic table, and X1, X2, or X3 ligand represents halogen, H2O, or a solvent molecule, and k represents a valence of a cation species, and Y represents an anion species, and L represents a valence of the anion species, and each of K and L independently represents 1 or 2, and k × m = L × n.
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Page/Page column 24
(2008/12/06)
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- Process for preparing optically active 3-azidocarboxylic acid derivatives and 3-aminocarboxylic acid derivatives
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A process for enantioselectively preparing 3-azidocarboxylic acid derivatives comprises reacting 3-sulfonatocarboxylic acid derivatives with an alkali metal azide in a solvent selected from the group comprising certain carboxamides; a solvent mixture which comprises such carboxamides; a solvent mixture of water and a solvent miscible homogeneously with water; water with the proviso that the addition of a phase transfer catalyst is not used in the reaction in water; and DMSO. The resulting products are optionally reduced to 3-aminocarboxylic acid derivatives.
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Page/Page column 8-10
(2008/06/13)
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- Reduction of carbonyl compounds with sodium borohydride in the presence of clays in aprotic solvents
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The selective reduction of carbonyl group of various aromatic and aliphatic compounds bearing different functional groups with sodium borohydride in the presence of clay in aprotic solvents give 72-93% yield of corresponding alcohols.
- Kumar, Anil,Chauhan
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p. 1038 - 1040
(2007/10/03)
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- Stereoselective enzymatic synthesis of chiral alcohols with the use of a carbonyl reductase from Candida magnoliae with anti-prelog enantioselectivity
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In our effort to search for carbonyl reductases with anti-Prelog enantioselectivity, the activity and enantioselectivity of a carbonyl reductase from Candida magnoliae have been examined with various ketones of diverse structures. This carbonyl reductase catalyzed the reduction of a series of ketones, α-and β-ketoesters, to anti-Prelog configurated alcohols in excellent optical purity. The usefulness of this carbonyl reductase has been demonstrated by synthesis of several chiral alcohol intermediates of pharmaceutical importance.
- Zhu, Dunming,Yang, Yan,Hua, Ling
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p. 4202 - 4205
(2007/10/03)
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- Solvent-free reduction of aldehydes and ketones using solid acid-activated sodium borohydride
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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
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p. 8164 - 8168
(2007/10/03)
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- Selective transfer hydrogenation of carbonyl compounds by ruthenium nanoclusters supported on alkali-exchanged zeolite beta
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Selective transfer hydrogenation of aromatic ketones and β-keto esters to the corresponding alcohols was achieved by using ruthenium nanoclusters supported on alkali-exchanged zeolite beta catalyst. The high activity and selectivity of the catalyst is due to the presence of highly dispersed ruthenium clusters in combination with the large number of Bronsted acidic sites of zeolite.
- Kantam, M. Lakshmi,Rao, B. Purna Chandra,Choudary,Sreedhar
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p. 1970 - 1976
(2007/10/03)
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- Synthesis of isotetronic acids by cyclization of 1,3-bis(trimethylsilyloxy) alk-1-enes with oxalyl chloride
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Isotetronic acids were regioselectively prepared by cyclization of 1,3-bis(trimethylsilyloxy)alk-1-enes with oxalyl chloride.
- Dede, Rüdiger,Michaelis, Lars,Langer, Peter
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p. 8129 - 8131
(2007/10/03)
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- ENZYMATIC PROCESSES FOR THE PRODUCTION OF 4-SUBSTITUTED 3-HYDROXYBUTYRIC ACID DERIVATIVES AND VICINAL CYANO, HYDROXY SUBSTITUTED CARBOXYLIC ACID ESTERS
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The present invention provides methods and composition for preparing 4-substituted 3-hydroxybutyric acid derivatives by halohydrin dehalogenase-catalyzed conversion of 4-halo-3-hydroxybutyric acid derivatives. The present invention further provides methods and compositions for preparing 4-halo-3-hydroxybutyric acid derivatives by ketoreductase-catalyzed conversion of 4-halo-3ketobutyric acid derivatives. The present invention also provides methods and compositions for preparing vicinal cyano, hydroxyl substituted carboxylic acid esters.
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Page/Page column 56
(2008/06/13)
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- Platinum carbonyl derived catalysts on inorganic and organic supports: A comparative study
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Fumed silica, silica gel, silica-alumina and cross-linked (5.5%) polystyrene have been functionalized with quaternary ammonium groups and the Chini cluster [Pt12(CO)24]2- has been anchored onto these functionalized materials by ion pairing. A catalyst has also been prepared by the adsorption of Na2[Pt12(CO)24] on unfunctionalized fumed silica. The catalytic activities of the resultant materials, and that of commercially purchased 5% platinum on alumina have been studied for the hydrogenation of a variety of unsaturated compounds. The substrates studied are: α-acetamidocinnamic acid, cyclohexanone, acetophenone, methyl pyruvate, ethyl acetoacetate, nitrobenzene and benzonitrile. Compared to the polystyrene supported catalyst, the inorganic oxide supported catalysts have higher surface areas and for most of the substrates have notably higher activities. The functionalized fumed silica-based catalyst gives higher conversions than functionalized silica gel and silica-alumina- based catalysts. In the hydrogenation of acetophenone and ethyl acetoacetate, the functionalized fumed silica-based catalyst show superior activity compared to the commercial platinum catalyst, and the catalyst made by conventional adsorption method. In benzonitrile hydrogenation with all the cluster-derived catalysts a hydrazine derivative is selectively formed, but when the commercial platinum catalyst is used benzyl amine is the main product.
- Paul, Himadri,Basu, Susmit,Bhaduri, Sumit,Lahiri, Goutam Kumar
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p. 309 - 316
(2007/10/03)
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- Sodium borohydride reduction and selective transesterification of β-keto esters in a one-pot reaction under mild conditions
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An efficient and simple one-pot method of preparing β-hydroxy esters by sodium borohydride reduction cum selective transesterification of β-keto esters under mild conditions is described.
- Padhi, Santosh Kumar,Chadha, Anju
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p. 639 - 642
(2007/10/03)
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- Methods of making intermediates from polyhydroxyalkanoates
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Methods of forming intermediates from PHAs are disclosed.
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- Direct Zn-diamine promoted reduction of C=O and C=N bonds by polymethylhydrosiloxane in methanol
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Ketones and imines are chemoselectively reduced at room temperature in methanol to the corresponding alcohols and amines in high yields in a one-step procedure using polymethylhydrosiloxane (PMHS) and a simple zinc-diamine catalyst.
- Bette, Virginie,Mortreux, Andre,Lehmann, Christian W.,Carpentier, Jean-Francois
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p. 332 - 333
(2007/10/03)
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- P-Stereogenic diphosphines in the ruthenium-catalysed asymmetric hydrogenation of C=C and C=O double bonds
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Bis(acetato) and dichloro complexes of ruthenium(II) containing P-stereogenic ligands have been prepared and tested in the asymmetric catalytic hydrogenation of functionalised olefins and keto esters. The best performance (52.6% ee) has been obtained in the hydrogenation of ethyl acetoacetate with [RuCl(PPh3)((S,S)-1,1′-bis(1-naphthylphenylphosphino) ferrocene)] 4.
- Maienza, Francesca,Santoro, Francesco,Spindler, Felix,Malan, Christophe,Mezzetti, Antonio
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p. 1817 - 1824
(2007/10/03)
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- Palladium-catalyzed reduction of ketones with nBu2SnH2
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Whereas the Pd(PPh3)4-catalyzed reduction of ketones with nBu3SnH does not proceed at all, the use of nBu2SnH2, instead of nBu3SnH, leads to the efficient reduction of a variety of ketones in the presence of a catalytic amount of Pd(PPh3)4 under mild conditions, providing the corresponding alcohols in good yields. The stereoselectivity in the reduction of cyclic ketones is also investigated by using this Pd(PPh3)4/nBu2SnH2 reduction system.
- Kamiya, Ikuyo,Ogawa, Akiya
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p. 1701 - 1703
(2007/10/03)
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- Synthesis of racemic 8-nonene-2,4-diol, acyclic precursor of 1,3-dimethyl-1,9-dioxabicyclo[3.1.1]nonane
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A new way of synthesis was developed for racemic 8-nonene-2,4-diol, the acyclic precursor of 1,3-dimethyl-1,9-dioxabicyclo[3.1.1]nonane. The latter substance was isolated from the bark of an ordinary spruce affected with a pest Trypodendron Lineatum Oliv.
- Vakhidov,Shakhmaev,Ishmuratov,Zorin
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p. 771 - 773
(2007/10/03)
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- Chemoselective transfer hydrogenation of carbonyl compounds catalyzed by macrocyclic nickel (II)complex
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Macrocyclic Ni(II) complex, 1, catalyzes efficiently the chemoselective transfer reduction of carbonyl compounds in presence of propan-2-ol/KOH or HCO2H/HCO2NH4 as hydrogen donors to produce the corresponding alcohols in high yield.
- Phukan, Prodeep,Sudalai
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p. 2401 - 2405
(2007/10/03)
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- Heteroaromatic diphosphines as chiral ligands
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Chiral diphosphines constituted by an aromatic pentatomic biheterocyclic system, suitable to act as chiral ligands, complexes between said diphosophines and transition metals, and their utilization as chiral catalysts in sterocontrolled reactions, such as diastereo- and enantioselective reduction reactions. Process for the preparation of said chiral diphosophines and process for the preparation of said complexes and for their utilization as chiral catalysts in sterocontrolled reactions.
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- Polymer-bound p-alkoxybenzyl trichloracetimidates: Reagents for the protection of alcohols as benzyl ethers on solid-phase
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Wang and Tentagel resins ware converted into their trichloroacetimidate dervatives and used as polymer-bound benzylating reagents for a variety of alcohols. Loading and cleavage proceed in good to excellent yields in the presence of BF3.OEt2 and 1% TFA respectively. The resins have excellent shelf life.
- Hanessian, Stephen,Xie, Fang
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p. 733 - 736
(2007/10/03)
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- Chemoselective carbonyl reduction of functionalised aldehydes and ketones to alcohols with sodium dithionite
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Sodium dithionite efficiently reduces carbonyl functionalities of functionalised aldehydes and ketones to corresponding alcohols in good yields without effecting the other functional groups in water/dioxane system at 85°C.
- Singh, Jasvinder,Kad, Goverdhan L.,Sharma, Munisha,Dhillon
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p. 2253 - 2257
(2007/10/03)
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- Efficient catalytic reduction of ketones with formic acid and ruthenium complexes
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The ruthenium complex (η5-C4Ph4COHOC4Ph4-η5)( μ-H)(CO)4Ru2 and its phenyl ring-substituted derivatives were found to act as efficient catalysts in reduction reactions of aldehydes and ketones to alcohols, using formic acid as H source. Excess formic acid accelerates the reaction, and the corresponding formate esters were isolated as sole products. Turnover numbers of up to 8000 (alcohols) and 11000 (formate esters) were attained, with yields in the order of 90%. Alkenes are not reactive, however, double bonds conjugated to a carbonyl group are selectively reduced under the reaction conditions. The reaction is compatible with a variety of ketones, but with aliphatic aldehydes the reaction is not selective, inasmuch as aldol condensation products are formed.
- Menashe, Naim,Salant, Einat,Shvo, Youval
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- Asymmetric hydrogenation of beta- or gamma-ketoesters and beta- or gamma-ketoamides
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β- or γ-Ketoesters and β- or γ-ketoamides are asymmetrically reduced with a Ru(II)-BINAP derived catalyst at about 40° C. and about 50N/mm2 of hydrogen in the presence of a strong acid.
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- Stereoselective synthesis of cyclopropanone ketals via silyl chloride promoted cyclization of β-zinciopropionates
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Alkyl, allyl, and propargyl β-iodopropionates undergo a cyclopropanation by the reaction with zinc-copper couple and TBDMSCI in THF to give 1-alkoxy-, 1-allyloxy- and 1-propargyloxy-1-tert-butyldimethylsiloxycyclopropanes in moderate or good yields. β-Iodo-α-methylpropionates 2 and 6 provide trans-5 and trans-8 selectively, which β-iodobutyrates 3 and 7 furnish cis-5 and cis-8 selectively.
- Yasui, Keigo,Tanaka, Shuji,Tamaru, Yoshinao
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p. 6881 - 6900
(2007/10/02)
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- The microbial reduction of 2-chloro-3-oxoesters
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Several aliphatic or aromatic 2-chloro-3-oxoesters are stereoselectively reduced by yeast or fungal strains, affording in fair to good yield and high enantiomeric excess some of the respective 2-chloro-3-hydroxyester stereoisomers.
- Cabon,Buisson,Larcheveque,Azerad
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p. 2199 - 2210
(2007/10/03)
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