- Hf-MOF catalyzed Meerwein?Ponndorf?Verley (MPV) reduction reaction: Insight into reaction mechanism
-
Hf-MOF-808 exhibits excellent activity and specific selectivity on the hydrogenation of carbonyl compounds via a hydrogen transfer strategy. Its superior activity than other Hf-MOFs is attributed to its poor crystallinity, defects and large specific surface area, thereby containing more Lewis acid-base sites which promote this reaction. Density functional theory (DFT) computations are performed to explore the catalytic mechanism. The results indicate that alcohol and ketone fill the defects of Hf-MOF to form a six-membered ring transition state (TS) complex, in which Hf as the center of Lewis stearic acid coordinates with the oxygen of the substrate molecule, thus effectively promoting hydrogen transfer process. Other reactive groups, such as –NO2, C = C, -CN, of inadequate hardness or large steric hindrance are difficult to coordinate with Hf, thus weakening their catalytic effect, which explains the specific selectivity Hf-MOF-808 for reducing the carbonyl group.
- Lin, Yamei,Bu, Qingxia,Xu, Jiaxian,Liu, Xiao,Zhang, Xueping,Lu, Guo-Ping,Zhou, Baojing
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- Cellulosic CuI Nanoparticles as a Heterogeneous, Recyclable Catalyst for the Borylation of α,β-Unsaturated Acceptors in Aqueous Media
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Abstract: We have demonstrated that cellulosic CuI nanoparticles could perform as an efficient heterogeneous catalyst for the synthesis of useful organoboron compounds. Desired β-borylation products were all obtained in good to excellent yields under mild
- Zhou, Lijie,Han, Biao,Zhang, Yaoyao,Li, Bojie,Wang, Liansheng,Wang, Jianying,Wang, Xianbao,Zhu, Lei
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p. 3220 - 3229
(2021/03/06)
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- Chiral Benzothiophene Synthesis via Enantiospecific Coupling of Benzothiophene S-Oxides with Boronic Esters
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Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. Herein, we report a general method for the synthesis of enantioenriched 2,3-disubstituted benzothiophenes via a transition-metal-free C2-alkylation of benzothiophenes with boronic esters. The reactions utilize benzothiophene S-oxides in lithiation-borylations to generate intermediate arylboronate complexes, and subsequent Tf2O-promoted S?O bond cleavage to trigger a Pummerer-type 1,2-metalate shift, which gives the coupled products with complete enantiospecificity. Primary, secondary and tertiary alkyl boronic esters and aryl boronic esters are successfully coupled with a range of C3-substituted benzothiophenes. Importantly, this transformation does not require the use of C3 directing groups, therefore it overcomes a major limitation of previously developed transition-metal-mediated C2 alkylations of benzothiophenes.
- Aggarwal, Varinder K.,Noble, Adam,Sang, Ruocheng
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p. 25313 - 25317
(2021/11/09)
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- Reaction of electrogenerated cyanomethyl anion with cyclohexylisocyanate: Synthesis of N-(cyclohexylcarbamoyl) acetamide. An unexpected product
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The contamination with water of the cathodic ACN-Et4NBF4 solution gave us the opportunity to investigate alkyl isocyanate reactivity toward electrogenerated anions. The cathodic reduction of a ACN-Et4NBF4 solution led to the formation of both hydroxide and cyanomethyl anions. The reaction of the catholyte with cyclohexylisocyanate led to the exclusive formation of acetamidated product, with no traces of cyanomethylated one. On the contrary, when reacting with benzaldehyde only the cyanomethylated was isolated. Considering that the acetamidated product of benzaldehyde is reported to be unstable (thus its formation cannot be excluded), various experiments were carried out in order to understand the anomalous reactivity of cyclohexylisocyanate. Moreover, computational analysis allowed to state the higher stability of acetamidated product with respect to the cyanomethylated one. The possibility of a concerted reaction, instead of acetamide anion formation prior to the reaction, is still an open question.
- Bortolami, Martina,Feroci, Marta,Pandolfi, Fabiana,Petrucci, Rita,Rocco, Daniele,Scarano, Vincenzo,Zollo, Giuseppe
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- Biocatalytic asymmetric ring-opening of dihydroisoxazoles: a cyanide-free route to complementary enantiomers of β-hydroxy nitriles from olefins
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By combination of the cyanide-free synthesis of chiral nitriles and the Kemp elimination reaction catalyzed by aldoxime dehydratases, we herein report a new application of aldoxime dehydratase in the asymmetric ring-opening of 5-sub-4,5-dihydroisoxazoles
- Asano, Yasuhisa,Zheng, Daijun
-
supporting information
p. 4930 - 4936
(2020/08/25)
-
- A Ball-Milling-Enabled Reformatsky Reaction
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An operationally simple one-jar one-step mechanochemical Reformatsky reaction using in situ generated organozinc intermediates under neat grinding conditions has been developed. Notable features of this reaction protocol are that it requires no solvent, no inert gases, and no pre-activation of the bulk zinc source. The developed process is demonstrated to have good substrate scope (39–82 % yield) and is effective irrespective of the initial morphology of the zinc source.
- Cao, Qun,Stark, Roderick T.,Fallis, Ian A.,Browne, Duncan L.
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p. 2554 - 2557
(2019/06/17)
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- Tuning Isonitrile/Tetrazine Chemistry for Accelerated Deprotection and Formation of Stable Conjugates
-
The isocyano group is a valuable functionality for bioorthogonal reactions because it rapidly reacts with tetrazines to either form stable conjugates or release payloads from 3-isocyanopropyl groups. Here we provide mechanistic insights into the dissociative steps that follow the initial cycloaddition and analyze how structural modifications affect these processes. Three main outcomes of this study have important implications for designing such groups for bioorthogonal applications. First, anion-stabilizing substituents at C-2 of the 3-isocyanopropyl group promote β-elimination and accelerate deprotection. Second, tetrazines with bulky substituents form stable imine conjugates even with primary isonitriles that are otherwise rapidly hydrolyzed. Third, the elimination step is independent from hydrolysis to the aldehyde and instead can occur directly from the imine intermediate. These findings will allow tuning the structures of tetrazine and isonitrile reactants for application in bioorthogonal ligation and release chemistry.
- Xu, Minghao,Deb, Titas,Tu, Julian,Franzini, Raphael M.
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p. 15520 - 15529
(2019/11/29)
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- RAPIDLY RELEASED BIOORTHOGONAL CAGING GROUPS
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Bioorthogonal molecules are disclosed and described. A bioorthogonal a molecule having a structure according to: Formula (I); where R2, R3, and R4 are independently selected from H, a substituted or unsubstituted C1/
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Page/Page column 35
(2019/12/25)
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- Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
-
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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- Mukaiyama addition of (trimethylsilyl)acetonitrile to dimethyl acetals mediated by trimethylsilyl trifluoromethanesulfonate
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(Trimethylsilyl)acetonitrile reacts smoothly with dimethyl acetals in the presence of stoichiometric trimethylsilyl trifluoromethanesulfonate (TMSOTf) to yield β-methoxynitriles. The ideal substrates for this reaction are acetals derived from aromatic aldehydes. Elimination to the corresponding α,β-unsaturated nitriles is observed as the major product in the case of electron-rich acetals. A mechanistic hypothesis that includes isomerization of the silylnitrile to a nucleophilic N-silyl ketene imine is presented.
- Downey, C. Wade,Lee, Alice Y.-K.,Goodin, John R.,Botelho, Courtney J.,Stith, William M.
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p. 3496 - 3499
(2017/10/05)
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- Extreme halophilic alcohol dehydrogenase mediated highly efficient syntheses of enantiopure aromatic alcohols
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Enzymatic synthesis of enantiopure aromatic secondary alcohols (including substituted, hetero-aromatic and bicyclic structures) was carried out using halophilic alcohol dehydrogenase ADH2 from Haloferax volcanii (HvADH2). This enzyme showed an unprecedented substrate scope and absolute enatioselectivity. The cofactor NADPH was used catalytically and regenerated in situ by the biocatalyst, in the presence of 5% ethanol. The efficiency of HvADH2 for the conversion of aromatic ketones was markedly influenced by the steric and electronic factors as well as the solubility of ketones in the reaction medium. Furthermore, carbonyl stretching band frequencies ν (CO) have been measured for different ketones to understand the effect of electron withdrawing or donating properties of the ketone substituents on the reaction rate catalyzed by HvADH2. Good correlation was observed between ν (CO) of methyl aryl-ketones and the reaction rate catalyzed by HvADH2. The enzyme catalyzed the reductions of ketone substrates on the preparative scale, demonstrating that HvADH2 would be a valuable biocatalyst for the preparation of chiral aromatic alcohols of pharmaceutical interest.
- Alsafadi, Diya,Alsalman, Safaa,Paradisi, Francesca
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p. 9169 - 9175
(2017/11/15)
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- Isomerization of 3-unsubstituted 4,5-dihydroisoxazoles over alumina. A new synthesis of β-hydroxy nitriles
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3-Unsubstituted 4,5-dihydroisoxazoles obtained by nitrosation of arylcyclopropanes are capable of undergoing efficient isomerization into 3-aryl-3-hydroxypropanenitriles during chromatography on alumina.
- Mochalov,Fedotov,Trofimova,Gazzaeva,Zefirov
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p. 397 - 403
(2016/06/13)
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- A green and recyclable chitosan supported catalyst for the borylation of α,β-unsaturated acceptors in water
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We herein report a green and recyclable chitosan supported copper catalyst which is capable of catalyzing the borylation of α,β-unsaturated acceptors in water at room temperature. A broad substrate scope including chalcone derivatives, esters and nitriles have been explored. In all the cases, desired products were obtained in good to excellent yields. Remarkably, this chitosan supported catalyst could be recovered and reused for five times without any significant decrease of reactivity.
- Xu, Pengyu,Li, Bojie,Wang, Liansheng,Qin, Caiqin,Zhu, Lei
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-
- A magnetic nanoparticle catalyzed eco-friendly synthesis of cyanohydrins in a deep eutectic solvent
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Magnetic Fe3O4 nanoparticles in deep eutectic solvents (DESs) have been regard as excellent catalysts for highly efficient cyanosilylation of various aldehydes and epoxides using trimethylsilyl cyanide TMSCN in high yields with excellent selectivity. Fe3O4 nanoparticles were synthesized and applied as a catalyst for the preparation of a wide variety of cyanohydrins (α-hydroxy nitriles and β-hydroxy nitriles) in readily available urea-choline chloride deep eutectic solvent DES as the most promising environmentally benign and cost-effective green solvent. Magnetic DES operates at very mild reaction conditions and can be easily recycled without significant loss of its catalytic activity.
- Azizi, Najmedin,Rahimi, Zahra,Alipour, Masoumeh
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p. 61191 - 61198
(2015/07/28)
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- Formation of carbanions from carboxylate ions bearing electron-withdrawing groups via photoinduced decarboxylation: Addition of generated carbanions to benzaldehyde
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The photoinduced decarboxylation of carboxylate ions bearing electron-withdrawing groups using biphenyl and 1,4-dicyanonaphthalene leads to the efficient generation of carbanions under mild conditions. The efficiency of the carbanion generation is strongl
- Kumagai, Yuta,Naoe, Takashi,Nishikawa, Keisuke,Osaka, Kazuyuki,Morita, Toshio,Yoshimi, Yasuharu
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p. 1668 - 1671
(2015/11/10)
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- Connecting Neutral and Cationic Pathways in Nickel-Catalyzed Insertion of Benzaldehyde into a C-H Bond of Acetonitrile
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Nickel catalysts supported by diethylamine- or aza-crown ether-containing aminophosphinite (NCOP) pincer ligands catalyze the insertion of benzaldehyde into a C-H bond of acetonitrile. The catalytic activity of neutral (NCOP)Ni(OtBu) and cation
- Smith, Jacob B.,Miller, Alexander J. M.
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p. 4669 - 4677
(2015/10/28)
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- Substrate evaluation of rhodococcus erythropolis SET1, a nitrile hydrolysing bacterium, demonstrating dual activity strongly dependent on nitrile sub-structure
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Assessment of Rhodococcus erythropolis SET1, a novel nitrile hydrolysing bacterial isolate, has been undertaken with 34 nitriles, 33 chiral and 1 prochiral. These substrates consist primarily of β-hydroxy nitriles with varying alkyl and aryl groups at the β position and containing in several compounds different substituents α to the nitrile. In the case of β-hydroxy nitriles without substitution at the α position, acids were the major products obtained, along with recovered nitrile after biotransformation, as a result of suspected nitrilase activity of the isolate. Unexpectedly, amides were found to be the major hydrolysis product when the β-hydroxy nitriles possessed a vinyl group at this position. To probe this behaviour further, additional related substrates were evaluated containing electron-withdrawing groups at the α position, and amide was also observed upon biotransformation in the presence of SET1. Therefore this novel isolate has also demonstrated NHase activity with nitriles that appears to be substrate-dependent.
- Coady, Tracey M.,Coffey, Lee V.,O'Reilly, Catherine,Lennon, Claire M.
-
supporting information
p. 1108 - 1116
(2015/02/19)
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- MCM-41 bound dibenzo-18-crown-6 ether: a recoverable phase-transfer nano catalyst for smooth and regioselective conversion of oxiranes to β-azidohydrins and β-cyanohydrins in water
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A new organic-inorganic hybrid nanocomposite was prepared by immobilizing dibenzo-18-crown-6 onto covalently linked amine functionalized mesoporous MCM-41 via a simple post-synthesis method. The heterogeneous hybrid nanocomposite was characterized by TEM,
- Yousefi, Sarah,Kiasat, Ali Reza
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p. 92387 - 92393
(2015/11/16)
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- Zinc-mediated addition of bromoacetonitrile to carbonyl compounds under solvent-free conditions
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Zinc mediated addition reaction of bromoacetonitrile with aryl aldehydes and ketones produces β-hydroxynitriles under solvent-free conditions. The valuable feature of the methodology are solvent-free and catalyst-free conditions and short reaction times (5 min).
- Zhang, Yumei,Du, Xi,An, Bin
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-
- Versatile iridicycle catalysts for highly efficient and chemoselective transfer hydrogenation of carbonyl compounds in water
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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
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supporting information
p. 12835 - 12842
(2015/03/30)
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- Steric vs. electronic effects in the Lactobacillus brevis ADH-catalyzed bioreduction of ketones
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Lactobacillus brevis ADH (LBADH) is an alcohol dehydrogenase that is commonly employed to reduce alkyl or aryl ketones usually bearing a methyl, an ethyl or a chloromethyl as a small ketone substituent to the corresponding (R)-alcohols. Herein we have tested a series of 24 acetophenone derivatives differing in their size and electronic properties for their reduction employing LBADH. After plotting the relative activity against the measured substrate volumes we observed that apart from the substrate size other effects must be responsible for the activity obtained. Compared to acetophenone (100% relative activity), other small substrates such as propiophenone, α,α, α-trifluoroacetophenone, α-hydroxyacetophenone, and benzoylacetonitrile had relative activities lower than 30%, while medium-sized ketones such as α-bromo-, α,α-dichloro-, and α,α-dibromoacetophenone presented relative activities between 70% and 550%. Moreover, the comparison between the enzymatic activity and the obtained final conversions using an excess or just 2.5 equiv. of the hydrogen donor 2-propanol, denoted again deviations between them. These data supported that these hydrogen transfer (HT) transformations are mainly thermodynamically controlled. For instance, bulky α-halogenated derivatives could be quantitatively reduced by LBADH even employing 2.5 equiv. of 2-propanol independently of their kinetic values. Finally, we found good correlations between the IR absorption band of the carbonyl groups and the degrees of conversion obtained in these HT processes, making this simple method a convenient tool to predict the success of these transformations. The Royal Society of Chemistry.
- Rodriguez, Cristina,Borzecka, Wioleta,Sattler, Johann H.,Kroutil, Wolfgang,Lavandera, Ivan,Gotor, Vicente
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supporting information
p. 673 - 681
(2014/01/06)
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- Facile synthesis of an organic-inorganic nanocomposite, PEG-silica, by sol-gel method; Its characterization and application as an efficient catalyst in regioselective nucleophilic ring opening of epoxides: Preparation of β-azido alcohols and β-cyanohydrin
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The sol-gel method was used for the synthesis of a PEG-silica hybrid. In order to introduce PEG into the cavities of silica gel, first, the bis(3-trimethoxysilylpropyl)-polyethylene glycol precursor was synthesized by the reaction of 3-chloropropyltrimeth
- Kiasat, Ali Reza,Nazari, Simin,Davarpanah, Jamal
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p. 124 - 130
(2014/03/21)
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- Multi-enzymatic biosynthesis of chiral β-hydroxy nitriles through co-expression of oxidoreductase and halohydrin dehalogenase
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To establish a system for the efficient one bacterial multi-enzymatic biosynthesis of both (R)- and (S)-β-hydroxy nitriles, we co-expressed alcohol dehydrogenases with opposite stereoselectivities, cofactor regeneration enzymes, and a halohydrin dehalogenase in Escherichia coli. By researching cofactor recycling and various co-expression strategies and by selecting and engineering the halohydrin dehalogenase, we engineered two E. coli strains, which were subsequently used in a cascade of reactions to produce chiral β-hydroxy nitriles with high enantiomeric excess directly from prochiral α-halo ketones. Three valuable pharmaceutical intermediates were prepared by means of this catalytic system, and substrate conversion reached about >99%. More importantly, the system is of low cost because there is no need for expensive cofactors or for expression and purification of the component enzymes. Copyright
- Chen, Shao-Yun,Yang, Chen-Xi,Wu, Jian-Ping,Xu, Gang,Yang, Li-Rong
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p. 3179 - 3190
(2013/12/04)
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- A robust nickel catalyst for cyanomethylation of aldehydes: Activation of acetonitrile under base-free conditions
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Nick of time: The nickel cyanomethyl complex 1 catalyzes the room temperature coupling of aldehydes with acetonitrile under base-free conditions. The catalytic system is long-lived and remarkably efficient with high turnover numbers (TONs) and turnover fr
- Chakraborty, Sumit,Patel, Yogi J.,Krause, Jeanette A.,Guan, Hairong
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supporting information
p. 7523 - 7526
(2013/07/26)
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- Catalytic asymmetric alkylation reactions for the construction of protected ethylene-amino and propylene-amino motifs attached to quaternary stereocentres
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An efficient catalytic and stereoselective method for the direct construction of protected ethylene-amino and propylene-amino scaffolds attached to quaternary stereocentres is reported. Preliminary investigations revealed a mild base catalysed nucleophilic ring opening of N-sulfonyl aziridines using the commercially available phosphazene base 2-tert-butylimino-2-diethylamino-1,3- dimethyl-perhydro-1,3,2-diazaphosphorine (BEMP) was possible and resulted in highly efficient alkylation reactions with a range of methine carbon acids. This reaction could be rendered highly asymmetric (up to 97 % ee) by employing phase-transfer catalysis to control stereoinduction. Incorporation of alkyl substituents onto the aziridine electrophile, resulted in a highly diastereoselective (up to 30:1 d.r.) variant of this methodology. A further extension using N-protected cyclic sulfamidates as the electrophilic component was successful with a range of pro-nucleophiles (up to 96 % ee and 45:1 d.r.) and allowed a range of nitrogen protecting groups (carbamate, sulfonyl, phosphonyl, benzyl) to be incorporated into the alkylation adducts. Finally, the utility of the products have been demonstrated in the synthesis of useful heterocycles and compounds bearing structural components of natural products. Open sesame: The enantio- and diastereoselective nucleophilic ring opening of protected aziridines and cyclic sulfamidates using asymmetric phase-transfer catalysis (PTC) is reported. The ring-opening alkylation reactions create quaternary chiral centres containing ethylene- and propylene-amino motifs in good yields with good to excellent enantioselectivities (see scheme). These reactions are broad in scope and a wide range of pro-nucleophiles are tolerated. Copyright
- Moss, Thomas A.,Barber, David M.,Kyle, Andrew F.,Dixon, Darren J.
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supporting information
p. 3071 - 3081
(2013/03/28)
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- Nucleophilic addition of α-(dimethylsilyl)nitriles to aldehydes and ketones
-
α-Alkylated (dimethylsilyl)acetonitriles (Me2HSiCR 3R4CN) react spontaneously with aldehydes in DMSO to give β-hydroxynitriles in good to high yields. The addition to ketones is effectively promoted by using MgCl2/su
- Jinzaki, Takaaki,Arakawa, Mitsuru,Kinoshita, Hidenori,Ichikawa, Junji,Miura, Katsukiyo
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supporting information
p. 3750 - 3753
(2013/08/23)
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- Highly regioselective conversion of epoxides to β-hydroxy nitriles using metal(II) Schiff base complexes as new catalysts under mild conditions
-
Epoxides undergo efficient ring opening with potassium cyanide in acetonitrile in the presence of metal Schiff base complexes as catalysts. This method was carried out under neutral and mild conditions with both high yields and high regioselectivity within a short period of time. Thus, several β-hydroxy nitriles, useful intermediates for the synthesis of biologically active molecules, were easily obtained at room temperature.
- Naeimi, Hossein,Karshenas, Azam
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p. 234 - 238
(2013/03/14)
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- RUTHENIUM-DIAMINE COMPLEXES AND METHOD FOR PRODUCING OPTICALLY ACTIVE COMPOUNDS
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Provided is a catalyst for asymmetric reduction, which can be produced by a convenient and safe production method, has a strong catalytic activity, and has excellent stereoselectivity. The present invention relates to a ruthenium complex represented by the following formula (1): wherein R1 represents an alkyl group or the like; Y represents a hydrogen atom; X represents a halogen atom or the like; j and k each represent 0 or 1; R2 and R3 each represent an alkyl group or the like; R11 to R19 each represent a hydrogen atom, an alkyl group or the like; Z represents oxygen or sulfur; n1 represents 1 or 2; and n2 represents an integer from 1 to 3, a method for producing the ruthenium complex, a catalyst for asymmetric reduction formed from the ruthenium complex, and methods for selectively producing an optically active alcohol and an optically active amine using the catalyst for asymmetric reduction.
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-
Page/Page column 23-24
(2012/03/26)
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- Metal or ammonium alginates as Lewis base catalysts for the 1,2-addition of silyl nucleophiles to carbonyl compounds
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Several metal (Na+, Ca2+) or ammonium (n-Bu 4N+) derivatives of alginic acid, an abundant bio-polymer obtained from the cell walls of brown algae, were synthesized. Their potential to act as organocatalysts to catalyze the 1,2-addition of various silyl derivatives to carbonyl compounds was evaluated for the first time. Ammonium alginate 1h is able to promote the reaction in modest to good isolated yields (up to 98%) affording access to a large range of substrates (β-cyano alcohols or ester, β-substituted methylacrylate or acrylonitrile, and cyanohydrin) by using only 5 mol % of catalyst.
- Verrier, Cécile,Oudeyer, Sylvain,Dez, Isabelle,Levacher, Vincent
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supporting information; experimental part
p. 1958 - 1960
(2012/05/19)
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- N-Heterocyclic carbene-catalyzed cyanomethylation of aldehydes with TMSAN
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N-Heterocyclic carbenes (NHCs) have been served as efficient catalysts for cyanomethylation of carbonyl compounds. In the presence of 5 mol % NHC, various aldehydes and 2,2,2-trifluoroacetophenone reacted with trimethylsilylacetonitrile (TMSAN) to give β-hydroxynitriles in moderate to high yields.
- Fan, Ye-Cheng,Du, Guang-Fen,Sun, Wan-Fu,Kang, Wei,He, Lin
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supporting information; experimental part
p. 2231 - 2233
(2012/05/20)
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- Development of a catalytic platform for nucleophilic substitution: Cyclopropenone-catalyzed chlorodehydration of alcohols
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Cyclopropenone makes the switch: 2,3-Bis-(p-methoxyphenyl)cyclopropenone is a highly efficient catalyst for the chlorodehydration of 20 diverse alcohol substrates (see scheme; X=Cl). With oxalyl chloride as catalytic activator, this nucleophilic substitution proceeded through cyclopropenium-activated intermediates and resulted in complete stereochemical inversion in substrates with chiral centers.
- Vanos, Christine M.,Lambert, Tristan H.
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supporting information; experimental part
p. 12222 - 12226
(2012/02/02)
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- One-pot nitrile aldolization/hydration operation giving β-hydroxy carboxamides
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Rhodium to the rescue: The formal aldol products of carboxamides (CONH 2) were obtained by using a RhI(OR) (R=H, Me) catalyst under essentially neutral pH and ambient conditions. This novel aldol strategy is based on the catalytic al
- Goto, Akihiro,Naka, Hiroshi,Noyori, Ryoji,Saito, Susumu
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supporting information; experimental part
p. 1740 - 1743
(2011/12/16)
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- LiOH-catalyzed simple ring opening of epoxides under solvent-free conditions
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LiOH has been found to be a very simple and selective catalyst for the rapid and mild synthesis of β-hydroxy sulfides and β-hydroxyl nitriles by ring opening of epoxides with aromatic, aliphatic, and heterocyclic thiols and trimethylsilyl cyanide at room temperature under solvent free conditions. All the reactions proceeded satisfactorily in short times and afforded the corresponding products in good to excellent yields with high regioselectivity and chemoselectivity under mild reaction conditions. Copyright Taylor & Francis Group, LLC.
- Azizi, Najmedin,Khajeh-Amiri, Alireza,Ghafuri, Hossein,Bolourtchian, Mohammad
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experimental part
p. 1550 - 1557
(2010/09/06)
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- Isoquinoline-based chiral monodentate N-heterocyclic carbenes
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C1-symmetric isoquinoline-based chiral diaminocarbene ligands (MIQ) have been developed to block three quadrants of the metal coordination sphere, complementing C2-symmetric biisoquinoline-based ligands (BIQ). MIQ-Cu complexes catalyzed conjugate borylation of various α,β-unsaturated amides in good yields (82-99%) and enantioselectivities (75-87% ee).
- Hirsch-Weil, Dimitri,Abboud, Khalil A.,Hong, Sukwon
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supporting information; experimental part
p. 7525 - 7527
(2010/12/18)
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- Reaction of Grignard reagents with carbonyl compounds under continuous flow conditions
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This contribution details how a continuous flow reactor was used to react carbonyl compounds with Grignard reagents at room temperature in an efficient and safe manner. Flow rate, residence time and temperature were optimized for the preparation of a small collection of secondary and tertiary alcohols. Excellent yields and general applicability were observed using the set-up protocol. The procedure was also applied for the preparation of Tramadol, an analgesic drug belonging to the opioid group. The developed conditions allowed the selective addition of Grignard reagents to aldehydes and ketones in the presence of a nitrile function.
- Riva,Gagliardi,Martinelli,Passarella,Vigo,Rencurosi
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experimental part
p. 3242 - 3247
(2010/05/19)
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- An environmentally benign catalytic method for efficient and selective nucleophilic ring opening of oxiranes by zirconium tetrakis(dodecyl Sulfate)
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An operationally simple and environmentally benign protocol for a highly regio- and chemoselective preparation of β-substituted alcohols by means of ring-opening reactions of oxiranes with various aliphatic alcohols, H 2O, NaN3 , and NaCN as nucleophiles in the presence of catalytic amounts of zirconium tetrakis(dodecyl sulfate) as Lewis acid/surfactant-combined catalysts (LASCs) was developed. The high efficiency of the catalyst was confirmed by the high product yields obtained within desired times and, in particularly by the reusability of the ZrIV complex.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Aliabadi, Marzieh
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scheme or table
p. 405 - 413
(2010/05/19)
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- P(i-PrNCH2CH2)3N as a Lewis base catalyst for the synthesis of β-hydroxynitriles using TMSAN
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(Equation Presented) Proazaphosphatrane 1a was found to be an efficient catalyst for synthesis of β-hydroxynitriles via the reaction of trimethylsilylacetonitrile (TMSAN) with aldehydes under mild reaction conditions and typically low catalyst loading (ca. 2 mol %). A variety of functional groups were tolerated, and good to excellent product yields were obtained.
- Wadhwa, Kuldeep,Verkade, John G.
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experimental part
p. 5683 - 5686
(2009/12/06)
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- Reaction of the electrogenerated cyanomethyl anion with carbonyl compounds: A clean and safe synthesis of β-hydroxynitriles
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The electrogenerated cyanomethyl anion reacts with carbonyl compounds to yield the corresponding β-hydroxymtriles in moderate to high yields. The reported methodology is very clean and safe, avoiding the use of any classical base or catalyst.
- Bianchi, Gabriele,Feroci, Marta,Rossi, Leucio
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experimental part
p. 3863 - 3866
(2010/01/11)
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- Biocatalytic cascade for the synthesis of enantiopure β-azidoalcohols and β-hydroxynitriles
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A three-step, two-enzyme, one-pot reaction sequence starting from prochiral a-chloroketones leading to enantiopure (3- azidoalcohols and (3-hydroxynitriles is described. Asymmetric bioreduction of a-chloroketones by hydrogen transfer catalysed by an alcohol dehydrogenase (ADH) established the stereogenic centre in the first step to furnish enantiopure chlorohydrin intermediates. Subsequent biocatalysed ring closure to the epoxide and nucleophilic ring opening with azide, N3-, or cyanide, CN-, both catalysed by a nonselective halohydrin dehalogenase (Hhe) proceeded with full retention of configuration to give enantiopure (-azidoalcohols and (3-hydroxynitriles, respectively. Both enantiomers of various optically pure (-azidoalcohols and (-hydroxynitriles were synthesised.
- Schrittwieser, Joerg H.,Lavandera, Ivan,Seisser, Birgit,Mautner, Barbara,Kroutil, Wolfgang
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supporting information; experimental part
p. 2293 - 2298
(2009/08/17)
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- Catalytic cyanomethylation of carbonyl compounds and imines with highly basic phosphine
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A highly basic phosphine, tris(2,4,6-trimethoxy phenyl)phosphine (TTMPP), catalyzes cyanomethylation using trimethylsilylacetonitrile (TMSCH2CN) to give the corresponding products in good to high yields, with both carbonyl compounds and imines.
- Matsukawa, Satoru,Kitazaki, Eri
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p. 2982 - 2984
(2008/09/20)
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- RhI-catalyzed aldol-type reaction of organonitriles under mild conditions
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An aldol-type reaction of organonitriles with aldehydes was catalyzed by a RhI(OR) species under ambient conditions, and the reaction displayed a broad substrate scope with respect to both organonitrile and aldehyde components. The Royal Societ
- Goto, Akihiro,Endo, Kohei,Ukai, Yu,Irle, Stephan,Saito, Susumu
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p. 2212 - 2214
(2008/12/22)
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- Catalytic nucleophilic activation of acetonitrile via a cooperative catalysis of cationic Ru complex, DBU, and NaPF6
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The development of an efficient catalytic system for the direct addition of acetonitrile under mild amine basic conditions is described. A cooperative catalysis of CpRu complex, DBU, and NaPF6 enables chemoselective and catalytic generation of
- Kumagai, Naoya,Matsunaga, Shigeki,Shibasaki, Masakatsu
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p. 8598 - 8608
(2008/02/10)
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- Metal(II) Schiff base complexes as catalysts for the high-regioselective conversion of epoxides to β-hydroxy nitriles in glycol solvents
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A facile preparation of 3-hydroxy propanenitrile derivatives is described involving ring opening of epoxides with potassium cyanide in glycol solvents in the presence of Schiff base complexes as catalysts. This method occurs under neutral and mild conditions with high yields and high regioselectivity. Thus, several β-Hydroxy nitriles, useful intermediates toward biologically-active molecules, are easily obtained at room temperature.
- Naeimi, Hossein,Moradian, Mohsen
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p. 1575 - 1579
(2007/10/03)
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- Unexpected stereorecognition in nitrilase-catalyzed hydrolysis of β-hydroxy nitriles
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Biocatalytic enantioselective hydrolysis of β-hydroxy nitriles to corresponding (S)-enriched β-hydroxy carboxylic acids has been achieved for the first time by an isolated nitrilase bII6402 from Bradyrhizobium japonicum USDA110. This offers a new "green" approach to optically pure β-hydroxy nitriles and β-hydroxy carboxylic acids. The observed remote stereorecognition is surprising because this nitrilase shows no enantioselectivity for the hydrolysis of α-hydroxy nitriles such as mandelonitrile.
- Kamila, Sukanta,Zhu, Dunming,Biehl, Edward R.,Hua, Ling
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p. 4429 - 4431
(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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- Efficient nickel catalyst for coupling of acetonitrile with aldehydes
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A Ni complex of a diarylamido-based PNP ligand is an efficient and robust catalyst for coupling of acetonitrile with aldehydes. The Royal Society of Chemistry 2005.
- Fan, Lei,Ozerov, Oleg V.
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p. 4450 - 4452
(2007/10/03)
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- Lewis base-catalyzed cyanomethylation of carbonyl compounds with (trimethylsilyl)acetonitrile
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Catalytic cyanomethylation of various carbonyl compounds with (trimethylsilyl)acetonitrile (TMSCH2CN) in the presence of Lewis bases such as cesium or lithium acetate proceeded smoothly to afford the corresponding cyanomethylated adducts in good yields. Copyright
- Kawano, Yoshikazu,Kaneko, Nobuya,Mukaiyama, Teruaki
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p. 1508 - 1509
(2007/10/03)
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- Method of manufacturing cyano compounds
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A method of manufacturing a cyano compound by reacting a carbonyl compound with a nitrile compound having at least one α-hydrogen atom in the presence of a ligand and a metal compound of formula (III), [in-line-formulae]MX??(III) [/in-line-formulae] where
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- METHOD FOR THE PREPARATION OF 3-SUBSTITUTED-3’-HYDROXYPROPIONITRILE
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The present invention relates to a method for the preparation of 3-substituted-3’-hydroxypropionitrile, more particularly, to a method for the preparation of 3-substituted-3’-hydroxypropionitrile which comprises performing ring opening of 1-substituted-ethylene oxide using sodium cyanide and citric acid in a range of pH 7.8 ~ 8.3 to provide 3-substituted-3’-hydroxypropionitrile in high optical purity and with high yield.
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Page/Page column 12
(2008/06/13)
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