- Hydroboration. 77. Revision of the Regioselectivity of the Hydroboration of Alkenes with Dihaloborane-Dimethyl Sulfide Complexes
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The hydroboration of alkanes with dihaloborane-dimethyl sulfide complexes (HBX2*SMe2, X = Cl, Br, and I) was systematically reexamined to establish the true regioselectivities in hydroboration with these reagents.Hydrogen halides (HX, X = Cl, Br, and I) liberated during the hydrolysis-oxidation of the alkyldihaloborane-dimethyl sulfide complexes (RBX2*SMe2) add to the residual alkene and hydrolyze to alcohols, thus introducing a significant error in the regioselectivity of such hydroborations.The true regioselectivities in the hydroboration of alkenes with HBX2*SMe2 reveal considerably smaller formation of secondary and tertiary derivatives than previously reported, a result that should significantly enhance the value of these hydroborating agents.
- Brown, Herbert C.,Racherla, Uday S.
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- Total Synthesis and Structure Revision of Boholamide A
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The 15-membered cyclic depsipeptide boholamide A and an epimer were prepared by total synthesis for the first time, thus leading to a revision of C6 stereochemistry in the originally proposed structure of natural boholamide A. This convergent route features achievement of a macro-lactamization step in a gram scale. The revised boholamide A was sythesized with 16 linear steps in 5.46% overall yield. This work facilitates the investigations of boholamide A as a potential hypoxia-selective anticancer agent.
- Han, Fangzhi,Liu, Guangju,Zhang, Xuhai,Ding, Yahui,Wang, Liang,Wu, Yijing,Chen, Yue,Zhang, Quan
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- Enantioselective Synthesis of the Proposed Structure of Santinol D
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In connection with structural verification of santinol D, a unique tricylglycerol isolated from Helichrysum italicum subsp. microphyllum, four possible isomers of its C-2'''and C-4''' centers were synthesized. The two enolizable chiral centers were installed with pre-defined absolute configurations using Evans alkylation and aldol condensation, respectively. The extra chiral center introduced in the aldol condensation was removed by Dess–Martin oxidation to convert the adjacent methine group into the highly enolizable subunit of an α-alkyl-β-keto ester at the end of the synthesis. The synthetic isomers provided unequivocal physical and NMR data for every single enantiomer and thus provided the information required for the configurational assignment of this natural product. With the aid of a model compound, the racemization of such species was examined polarimetrically under several sets of typical conditions and the rates were also calculated from the corresponding kinetics data.
- Xiong, Xin,Wu, Yikang,Liu, Bo
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- ORGANOBORANES FOR SYNTHESIS. 5. STOICHIOMETRICALLY CONTROLLED REACTION OF ORGANOBORANES WITH OXYGEN UNDER MILD CONDITIONS TO ACHIEVE QUANTITATIVE CONVERSION TO ALCOHOLS
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The reaction of organoboranes with oxygen under mild conditions can be controlled to give an essentially quantitative conversion of all three alkyl groups on boron to the corresponding alcohol.The controlled oxidation is a very clean reaction, with only minor amounts of carbonyl and hydrocarbon products formed.All organoboranes react quite rapidly in the initial stages, but vary considerably in the time required to achieve the desired uptake of oxygen.In contrast to oxidation by alkaline hydrogen peroxide, a portion of this reaction proceeds through alkyl radicals, thus resulting in some loss of stereospecificity.Oxidation of mixed organoboranes reveals that the relative rates of oxidation of alkyl groups on boron are consistent with a radical mechanism, with tertiary > secondary > primary in the rate of oxidation.The selective oxidation of one alkyl group in the presence of the other is not possible, due to small differences in relative rates of oxidation.However, thexyl and cyclohexyl groups can be selectively removed from boron in the presence of alkenyl groups.Thus, controlled oxidation of thexyldialkenylborane affords pure dialkenylborinic acid.
- Brown, Herbert C.,Midland, M. Mark,Kabalka, George W.
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- A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid Drakaea micrantha
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Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed β-hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations.
- Bohman, Bj?rn,Tan, Monica M. Y.,Phillips, Ryan D.,Scaffidi, Adrian,Sobolev, Alexandre N.,Moggach, Stephen A.,Flematti, Gavin R.,Peakall, Rod
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- ORGANOBORANES FOR SYNTHESIS. 6. A CONVENIENT, GENERAL SYNTHESIS OF ALKYLHYDROPEROXIDES via AUTOXIDATION OF ORGANOBORANES
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The low temperature autoxidation of organoboranes in tetrahydrofuran leads to the formation of diperoxyboranes, which provide the corresponding alkylhydroperoxides in excellent yields, upon treatment with hydrogen peroxide.However, only two of the three alkyl groups on boron are used for the formation of hydroperoxides.This difficulty was solved by employing alkyldichloroborane etherates instead of trialkylboranes.The alkyldichloroborane etherates react cleanly with one molar equivalent of oxygen in ether solvent.The product is readily hydrolyzed to form the corresponding hydroperoxides in excellent yields.The autoxidation of organoboranes is inhibited by iodine or such free-radical scavengers.A study of the inhibition by iodine of the oxidation of representative trialkylboranes indicates that the rate of initiation decreases with an increase in the steric crowding about the boron atom.The rate of inhibition of the autoxidation of trialkylboranes by iodine reveals that the reaction involves a relatively slow rate of radical initiation, followed by a very fast rate of chain propagation.
- Brown, Herbert C.,Midland, M. Mark
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- Cp2TiCl2-catalyzed grignard reactions. 2. Reactions with ketones and aldehydes
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The reaction of Grignard reagents with ketones or aldehydes in the presence of a catalytic amount of Cp2TiCl2 leads to the corresponding reduction products in high yields. Cp2TiH intermediate was proposed to account for this observation.
- Sato, Fumie,Jinbo, Takamasa,Sato, Masao
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- Widely applicable synthesis of enantiomerically pure tertiary alkyl-containing 1-alkanols by zirconium-catalyzed asymmetric carboalumination of alkenes and palladium- or copper-catalyzed cross-coupling
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A highly enantioselective and widely applicable method for the synthesis of various chiral 2-alkyl-1-alkanols, especially those of feeble chirality, has been developed. It consists of zirconium-catalyzed asymmetric carboalumination of alkenes (ZACA), lipase-catalyzed acetylation, and palladium- or copper-catalyzed cross-coupling. By virtue of the high selectivity factor (E) associated with iodine, either (S)- or (R)-enantiomer of 3-iodo-2-alkyl-1- alkanols (1), prepared by ZACA reaction of allyl alcohol, can be readily purified to the level of ≥99 % ee by lipase-catalyzed acetylation. A variety of chiral tertiary alkyl-containing alcohols, including those that have been otherwise difficult to prepare, can now be synthesized in high enantiomeric purity by Pd- or Cu-catalyzed cross-coupling of (S)-1 or (R)-2 for introduction of various primary, secondary, and tertiary carbon groups with retention of all carbon skeletal features. These chiral tertiary alkyl-containing alcohols can be further converted into the corresponding acids with full retention of the stereochemistry. The synthetic utility of this method has been demonstrated in the highly enantioselective (≥99 % ee) and efficient syntheses of (R)-2-methyl-1-butanol and (R)- and (S)-arundic acids. Look, mom, one hand! 2-Alkyl-1-alkanols of feeble chirality have been synthesized by a sequence of zirconium-catalyzed asymmetric carboalumination of alkenes (ZACA), lipase-catalyzed acetylation, and Pd- or Cu-catalyzed cross-coupling in high enantiomeric purity of ≥99 % ee. The synthetic utility of this method has been demonstrated in highly enantioselective and efficient syntheses of (R)-2-methyl-1-butanol, (R)- and (S)-arundic acids. Copyright
- Xu, Shiqing,Lee, Ching-Tien,Wang, Guangwei,Negishi, Ei-Ichi
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- Synthesis and fungicidal activity of 2-methylalkyl isonicotinates and nicotinates
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Abstract: Homologs and analogs of 2-methylheptyl isonicotinate (new, natural antifungal and antibacterial antibiotic isolated from Streptomyces sp. 201): racemic 2-methylalkyl isonicotinates 4 and nicotinates 5 and enantiomerically enriched in the R and S isomers, 2-methylpentyl isonicotinate and nicotinate were obtained. Fungistatic activity of the compounds was evaluated. Nicotinates 5a–c show significant activity against phytopathogenic fungi: Fusarium culmorum, Phytophthora cactorum, Rhizoctonia solani. The activity of the enantiomerically enriched compounds was comparable to the activity of racemic ones. There was no significant difference in fungistatic activity between the enantiomerically enriched R and S isomers. Investigated compounds and their oxalates have proven to be active against chalkbrood disease caused by fungal species Ascosphaera apis. The activity of the nicotinates 5a and 5b and oxalates 5a–c against Ascosphaera apis was higher than the activity of oxalic acid itself. Especially high activity was shown for 2-methylbutyl nicotinate 5a and oxalate of 2-methylpentyl nicotinate 5b. Graphical abstract: [InlineMediaObject not available: see fulltext.]
- Huras, Bogumi?a,Zakrzewski, Jerzy,Krawczyk, Maria,Bombińska, Danuta,Cieniecka-Ros?onkiewicz, Anna,Michalczyk, Alicja
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- Characterization of active sites over reduced Ni-Mo/Al2O 3 catalysts for hydrogenation of linear aldehydes
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Reduced Ni-Mo/Al2O3 catalysts exhibit a behavior analogous to that of sulfided Ni-Mo/Al2O3 catalysts in hydrogenation of linear aldehydes to alcohols. Similar to what has been previously reported for sulfided catalysts, NO and CO2 can be used over the reduced Ni-Mo catalysts as probe molecules for the active sites responsible for two competing reactions - aldehyde hydrogenation to alcohols and condensation reactions to heavy products, respectively. Reduced catalysts have a higher aldehyde conversion activity and alcohol selectivity than their sulfided counterparts. The reduction temperature has a strong effect on the surface density of anion vacancies, which are responsible for alcohol formation. Reduction temperature also plays a role in determining the abundance of OH groups on the alumina surface. The effect of reduction temperature also manifests itself through the differences seen in the oxidation states of Mo and Ni species.
- Wang, Xueqin,Ozkan, Umit S.
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- SODIUM PERCARBONATE: A CONVENIENT REAGENT FOR EFFICIENTLY OXIDIZING ORGANOBORANES
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Sodium percarbonate, a readily available, inexpensive and easy to handle reagent, efficiently oxidizes organoboranes.The yields of alcohols are essentially identical to those obtained using standard oxidation procedure.
- Kabalka, George W.,Wadgaonkar, Prakash P.,Shoup, Timothy M.
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- Direct Generation of Triketide Stereopolyads via Merged Redox-Construction Events: Total Synthesis of (+)-Zincophorin Methyl Ester
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(+)-Zincophorin methyl ester is prepared in 13 steps (longest linear sequence). A bidirectional redox-triggered double anti-crotylation of 2-methyl-1,3-propane diol directly assembles the triketide stereopolyad spanning C4-C12, significantly enhancing step economy and enabling construction of (+)-zincophorin methyl ester in nearly half the steps previously required.
- Kasun, Zachary A.,Gao, Xin,Lipinski, Radoslaw M.,Krische, Michael J.
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- Lipase-catalyzed resolution of racemic 2-alkyl substituted 1-alkanols
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(R)-2-alkyl-1-alkanoids (R)-1 with high optical purities were obtained by lipase-catalyzed esterification of the racemic substrates (R,S)-1 with vinyl acetate in dichloromethane. The alcohols (R)-1 were oxidized without racemization to the corresponding carboxylic acids (R)-4. The enriched (S)-acetates (S)-3 either were saponified to the alcohols (S)-1 which are substrates for a second lipase-catalyzed transesterification to give (S)-1 in high optical purity or were racemized and applied once again in the kinetic resolution to prepare (R)-1.
- Barth,Effenberger
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- Reaction network of aldehyde hydrogenation over sulfided Ni-Mo/Al 2O3 catalysts
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A reaction network of aldehyde hydrogenation over NiMoS/Al 2O3 catalysts was studied with aldehydes with straight and branched carbon chains and different chain lengths as feed materials. The reactions in the gas phase and the liquid phase were compared. The main reaction in the aldehyde hydrogenation process is the hydrogenation of the CO double bond, which takes place over the coordinatively unsaturated sites. The major side reactions are self-condensation of aldehydes and condensation of aldehydes with alcohols. Both reactions involve α-hydrogen and are primarily catalyzed by acid-base bifunctional sites over the exposed Al2O 3 surfaces.
- Wang, Xueqin,Saleh, Ramzi Y.,Ozkan, Umit S.
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- Iridium Clusters Encapsulated in Carbon Nanospheres as Nanocatalysts for Methylation of (Bio)Alcohols
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C?H methylation is an attractive chemical transformation for C?C bonds construction in organic chemistry, yet efficient methylation of readily available (bio)alcohols in water using methanol as sustainable C1 feedstock is limited. Herein, iridium nanocatalysts encapsulated in yolk–shell-structured mesoporous carbon nanospheres (Ir@YSMCNs) were synthesized for this transformation. Monodispersed Ir clusters (ca. 1.0 nm) were encapsulated in situ and spatially isolated within YSMCNs by a silica-assisted sol–gel emulsion strategy. A selection of (bio)alcohols (19 examples) was selectively methylated in aqueous phase with good-to-high yields over the developed Ir@YSMCNs. The improved catalytic efficiencies in terms of activity and selectivity together with the good stability and recyclability were contributable to the ultrasmall Ir clusters with oxidation chemical state as a consequence of the confinement effect of YSMCNs with interconnected nanostructures.
- Liu, Qiang,Xu, Guoqiang,Wang, Zhendong,Liu, Xiaoran,Wang, Xicheng,Dong, Linlin,Mu, Xindong,Liu, Huizhou
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- Etherification of aldehydes, alcohols and their mixtures on Pd/SiO2 catalysts
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Dialkyl ethers have been selectively produced from etherification of aldehydes and alcohols on supported Pd catalysts. A yield of 79% ether with a selectivity of 90% was observed when feeding 2-methylpentanal with 2-methylpentanol at a molar ratio 1:1 at 125 °C. Cross etherification of n-butanol with 2-methylpentanal shows a much higher rate than that observed when the alcohol or aldehyde is fed alone. This enhanced activity is in line with the catalyst requirement for large ensembles that allow surface alkoxide species next to η2 adsorbed aldehydes. Etherification when only aldehyde or alcohol is fed arises predominantly due to aldehyde-alcohol inter-conversion to produce the necessary co-reactant. The ether yield at the same reaction conditions decreases with metal loading in the order 16 > 10 > 3 wt.% Pd. Increasing reduction temperature also increases ether yield. It is apparent that etherification is highly sensitive to metal particle morphology, consistent with needing ensembles that accommodate the two adjacent adsorption sites.
- Pham, Trung T.,Crossley, Steven. P.,Sooknoi, Tawan,Lobban, Lance L.,Resasco, Daniel E.,Mallinson, Richard G.
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- Development of a practical biocatalytic process for (R)-2-methylpentanol
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(R)-2-Methylpentanol is an important chiral intermediate for the synthesis of certain medicinally important compounds, natural products, and liquid crystals. Here we describe the development of a practical kinetic resolution utilizing an enantiospecific bio - catalytic reduction of racemic 2-methylvaleraldehyde. The process utilizes an evolved ketoreductase enzyme to selectively reduce the (R)-enantiomer of racemic 2-methylvaleraldehyde to the desired product with high volumetric productivity. A scaleable method for separating the desired product from the off-enantiomer of the starting material is also described. The process is cost-effective, green, and amenable to manufacturing scale.
- Gooding, Owen W.,Voladri, Rama,Bautista, Abigail,Hopkins, Thutam,Huisman, Gjalt,Jenne, Stephan,Ma, Steven,Mundorff, Emily C.,Savile, Megan M.,Truesdell, Susan J.,Wong, John W.
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- Asymmetric Oxidoreductions Catalyzed by Alcohol Dehydrogenase in Organic Solvents
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A methodology is developed for the use of alcohol dehydrogenase (and other NAD+/NADH-dependent enzymes) as catalysts in organic solvents.The enzyme and the cofactor are deposited onto the surface of glass beads which are then suspended in a water-immiscible organic solvent containing the substrate.Both NADH and NAD+ are efficiently regenerated in such a system with alcohol dehydrogenase-catalyzed oxidation of ethanol and reduction of isobutyraldehyde, respectively; cofactor turnover numbers of 1E5 to greater than 1E6 have been obtained.With use of asymmetric oxidoreductions catalyzed by horse liver alcohol dehydrogenase in isopropyl ether, optically active (ee of 95 to 100percent) alcohols and ketones have been prepared on a 1 to 10 mmol scale.
- Grunwald, Jacob,Wirz, Beat,Scollar, Mark P.,Klibanov, Alexander M.
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- Hydrogenation of Esters by Manganese Catalysts
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The hydrogenation of esters catalyzed by a manganese complex of phosphine-aminopyridine ligand was developed. Using this protocol, a variety of (hetero)aromatic and aliphatic carboxylates including biomass-derived esters and lactones were hydrogenated to primary alcohols with 63–98% yields. The manganese catalyst was found to be active for the hydrogenation of methyl benzoate, providing benzyl alcohol with turnover numbers (TON) as high as 45,000. Investigation of catalyst intermediates indicated that the amido manganese complex was the active catalyst species for the reaction. (Figure presented.).
- Li, Fu,Li, Xiao-Gen,Xiao, Li-Jun,Xie, Jian-Hua,Xu, Yue,Zhou, Qi-Lin
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- Selective, base-free hydrogenation of aldehydes catalyzed by IR complexes based on proton-responsive lutidine-derived CNP ligands
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Metal catalysts based on ligands containing proton-responsive sites have found widespread applications in the hydrogenation of polar unsaturated substrates. In this contribution, Ir complexes incorporating lutidine-derived CNP (C = N-heterocyclic carbene, NHC; P = phosphine) pincer ligands with two nonequivalent Br?nsted acid/base sites have been examined in the hydrogenation of aldehydes. To this end, Ir(CNP)H2Cl complexes were synthesized in two steps from the CNP ligand precursors and Ir(acac)(COD). These derivatives react with an excess of NaH to yield the trihydride derivatives Ir(CNP)H3, which were assessed as catalyst precursors in the hydrogenation of a series of aldehydes. The catalytic reactions were performed using commercial-grade substrates under neutral, mild conditions (0.1 mol % Ir-CNP; 4 bar H2, room temperature) with high conversions and selectivities for the reduction of the carbonyl function in the presence of other readily reducible groups such as C=C, nitro, and halogens. Reaction of an Ir(CNP)H2Cl complex with base in the presence of an aromatic aldehyde produces the reversible formation of alkoxide Ir complexes in which the aldehyde is bound to the deprotonated pincer framework (CNP*) through the CH-NHC arm of the ligand. These species, along with a carboxylate complex resulting from the Ir mediated oxidation of the aldehyde by water, is observed in the reaction of Ir(CNP)H3 with benzaldehyde. Finally, investigation of the mechanism of the hydrogenation of aldehydes has been carried out by means of DFT calculations considering the involvement of each arm of the Ir-CNP/CNP* derivatives. Calculations support a mechanism in which the catalyst switches its metal?ligand cooperation sites to follow the lowest energy pathway for each step of the catalytic cycle.
- álvarez, Eleuterio,Hernández-Juárez, Martín,López-Serrano, Joaquín,Paneque, Margarita,Rendón, Nuria,Sánchez, Práxedes,Suárez, Andrés
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p. 1314 - 1327
(2021/05/31)
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- Zeolite-Encaged Isolated Platinum Ions Enable Heterolytic Dihydrogen Activation and Selective Hydrogenations
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Understanding the unique behaviors of atomically dispersed catalysts and the origin thereof is a challenging topic. Herein, we demonstrate a facile strategy to encapsulate Ptδ+ species within Y zeolite and reveal the nature of selective hydrogenation over a Pt@Y model catalyst. The unique configuration of Pt@Y, namely atomically dispersed Ptδ+ stabilized by the surrounding oxygen atoms of six-membered rings shared by sodalite cages and supercages, enables the exclusive heterolytic activation of dihydrogen over Ptδ+···O2- units, resembling the well-known classical Lewis pairs. The charged hydrogen species, i.e., H+ and Hδ-, are active reagents for selective hydrogenations, and therefore, the Pt@Y catalyst exhibits remarkable performance in the selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols and of nitroarenes to arylamines.
- Dai, Weili,Deng, Xin,Guan, Naijia,Li, Landong,Liu, Runze,Ma, Ding,Qin, Bin,Qin, Xuetao,Wu, Guangjun
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supporting information
p. 20898 - 20906
(2021/12/14)
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- Iridium-Catalyzed Domino Hydroformylation/Hydrogenation of Olefins to Alcohols: Synergy of Two Ligands
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A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.
- Beller, Matthias,Huang, Weiheng,Jackstell, Ralf,Jiao, Haijun,Tian, Xinxin
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supporting information
(2022/01/13)
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- Carbon monoxide and hydrogen (syngas) as a C1-building block for selective catalytic methylation
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A catalytic reaction using syngas (CO/H2) as feedstock for the selective β-methylation of alcohols was developed whereby carbon monoxide acts as a C1 source and hydrogen gas as a reducing agent. The overall transformation occurs through an intricate network of metal-catalyzed and base-mediated reactions. The molecular complex [Mn(CO)2Br[HN(C2H4PiPr2)2]]1comprising earth-abundant manganese acts as the metal component in the catalytic system enabling the generation of formaldehyde from syngas in a synthetically useful reaction. This new syngas conversion opens pathways to install methyl branches at sp3carbon centers utilizing renewable feedstocks and energy for the synthesis of biologically active compounds, fine chemicals, and advanced biofuels.
- Kaithal, Akash,H?lscher, Markus,Leitner, Walter
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p. 976 - 982
(2021/02/06)
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- Manganese(I)-Catalyzed β-Methylation of Alcohols Using Methanol as C1 Source
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Highly selective β-methylation of alcohols was achieved using an earth-abundant first row transition metal in the air stable molecular manganese complex [Mn(CO)2Br[HN(C2H4PiPr2)2]] 1 ([HN(C2H4PiPr2)2]=MACHO-iPr). The reaction requires only low loadings of 1 (0.5 mol %), methanolate as base and MeOH as methylation reagent as well as solvent. Various alcohols were β-methylated with very good selectivity (>99 %) and excellent yield (up to 94 %). Biomass derived aliphatic alcohols and diols were also selectively methylated on the β-position, opening a pathway to “biohybrid” molecules constructed entirely from non-fossil carbon. Mechanistic studies indicate that the reaction proceeds through a borrowing hydrogen pathway involving metal–ligand cooperation at the Mn-pincer complex. This transformation provides a convenient, economical, and environmentally benign pathway for the selective C?C bond formation with potential applications for the preparation of advanced biofuels, fine chemicals, and biologically active molecules.
- Kaithal, Akash,van Bonn, Pit,H?lscher, Markus,Leitner, Walter
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supporting information
p. 215 - 220
(2019/12/03)
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- Synthesis and mass spectra of rearrangement bio-signature metabolites of anaerobic alkane degradation via fumarate addition
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Metabolite profiling in anaerobic alkane biodegradation plays an important role in revealing activation mechanisms. Apart from alkylsuccinates, which are considered to be the usual biomarkers via fumarate addition, the downstream metabolites of C-skeleton rearrangement can also be regarded as biomarkers. However, it is difficult to detect intermediate metabolites in both environmental samples and enrichment cultures, resulting in lacking direct evidence to prove the occurrence of fumarate addition pathway. In this work, a synthetic method of rearrangement metabolites was established. Four compounds, namely, propylmalonic acid, 2-(2-methylbutyl)malonic acid, 2-(2-methylpentyl)malonic acid and 2-(2-methyloctyl)malonic acid, were synthesized and determined by four derivatization approaches. Besides, their mass spectra were obtained. Four characteristic ions were observed at m/z 133 + 14n, 160 + 28n, 173 + 28n and [M - (45 + 14n)]+ (n = 0 and 2 for ethyl and n-butyl esters, respectively). For methyl esterification, mass spectral features were m/z 132, 145 and [M - 31]+, while for silylation, fragments were m/z 73, 147, 217, 248, 261 and [M - 15]+. These data provide basis on identification of potential rearrangement metabolites in anaerobic alkane biodegradation via fumarate addition.
- Chen, Jing,Zhou, Lei,Liu, Yi-Fan,Hou, Zhao-Wei,Li, Wei,Mbadinga, Serge Maurice,Zhou, Jing,Yang, Tao,Liu, Jin-Feng,Yang, Shi-Zhong,Wu, Xiao-Lin,Gu, Ji-Dong,Mu, Bo-Zhong
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- Desymmetrization of C2-Symmetric Bis(Boronic Esters) by Zweifel Olefinations
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anti-Configured 1,3-dimethyl deoxypropionate motifs are important sub structures in natural products. Herein, we describe a bidirectional approach for the rapid construction of natural products featuring such motifs by using C2-symmetrical 1,3-bis(boronic esters). As for its application in convergent syntheses it was important to establish a selective mono-Zweifel olefination we describe the scope and limitations by using different 1,3-bis(boronic esters) and nucleophiles. This protocol takes advantage of the combination of the Hoppe–Matteson–Zweifel chemistry, which was elegantly put into practice by Aggarwal et al. In order to show its applicability the total syntheses of two natural products, serricornin and (+)-invictolide, were performed.
- Linne, Yannick,Sch?nwald, Axel,Wei?bach, Sebastian,Kalesse, Markus
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supporting information
p. 7998 - 8002
(2020/06/09)
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- Diastereoselective synthesis of functionally substituted alkene dimers and oligomers, catalysed by chiral zirconocenes
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The research addresses the reaction of terminal alkenes and propene with AlR3 (R = Me, Et) in the presence of chiral Zr complexes, rac-[Y(η5-C9H10)2]ZrCl2 (Y = C2H4, SiMe2) or (NMI)2ZrCl2 (NMI- η5–neomenthylindenyl), and methylaluminoxane. The effect of reaction conditions, catalyst and trialkylalane structure on the substrate conversion and the reaction chemo- and stereoselectivity has been studied. The reaction predominantly goes via the stage of alkene methyl(ethyl)zirconation with subsequent introduction of substrate molecules into the Zr-C bond. As a result, a diastereoselective one-pot method for the synthesis of functionally substituted linear terminal alkene dimers and propene oligomers was developed.
- Kovyazin, Pavel V.,Abdullin, Il'giz N.,Parfenova, Lyudmila V.
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p. 144 - 152
(2018/11/21)
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- Ruthenium(II)-Catalyzed β-Methylation of Alcohols using Methanol as C1 Source
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Selective introduction of methyl branches into the carbon chains of alcohols can be achieved with low loadings of ruthenium precatalyst [RuH(CO)(BH4)(HN(C2H4PPh2)2)] (Ru-MACHO-BH) using methanol both as methylating reagent and as reaction medium. A wide range of structurally divers alcohols was β-methylated with excellent selectivity (>99 %) in fair to high yields (up to 94 %) under standard conditions, and turnover numbers up to 18,000 could be established. The overall reaction rate of the complex catalytic network appears to be governed by interconnection of the individual subcycles through availability of the reactive intermediates. The synthetic procedure opens pathways to important structural motifs following the Green Chemistry principles.
- Kaithal, Akash,Schmitz, Marc,H?lscher, Markus,Leitner, Walter
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p. 5287 - 5291
(2019/05/28)
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- Synthesis of β-Chiral Amines by Dynamic Kinetic Resolution of α-Branched Aldehydes Applying Imine Reductases
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Imine reductases (IREDs) allow the one-step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α-chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β-chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α-chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α-branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2-phenylpropanal and a substituted 2-methyl-3-phenylpropanal: the corresponding N-methylated β-chiral amines were obtained with '95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one-step synthesis of secondary β-chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.
- Matzel, Philipp,Wenske, Sebastian,Merdivan, Simon,Günther, Sebastian,H?hne, Matthias
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p. 4281 - 4285
(2019/08/20)
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- Efficient conversion of ethanol to 1-butanol and C5-C9 alcohols over calcium carbide
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Production of 1-butanol or alcohols with 4-9 carbon atoms (C4-C9 alcohols) from widely available bio-ethanol has attracted much interest in recent years in academia and industry of renewable chemicals and liquid fuels. This work discloses for the first time that calcium carbide (CaC2) has a superior catalytic activity in condensation of ethanol to C4-C9 alcohols at 275-300 °C. The 1-butanol yield reached up to 24.5% with ethanol conversion of 62.4% at the optimized conditions. The by-products are mainly alcohols with 5-9 carbons besides 2-butanol, and the total yield of all the alcohols reached up to 56.3%. The reaction route was investigated through controlled experiments and quantitative analysis of the products. Results indicated that two reaction routes, aldol-condensation and self-condensation, took place simultaneously. The aldol-condensation route involves coupling of ethanol with acetaldehyde (formed from ethanol dehydrogenation) to form 2-butenol, which is subsequently hydrogenated to 1-butanol. The alkynyl moiety in CaC2 plays an important role in the catalytic pathways of both routes and affords the good activity of CaC2. CaC2 is converted to acetylene [C2H2] and calcium hydroxide [Ca(OH)2] simultaneously by the H2O that was generated from the condensation of alcohols.
- Wang, Dong,Liu, Zhenyu,Liu, Qingya
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p. 18941 - 18948
(2019/07/04)
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- Iron Catalyzed Hydroboration of Aldehydes and Ketones
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We report an operationally convenient room temperature hydroboration of aldehydes and ketones employing Fe(acac)3 as precatalyst. The hydroboration of aldehydes and ketones proceeded efficiently at room temperature to yield, after work up, 1° and 2° alcohols; chemoselective hydroboration of aldehydes over ketones is attained under these conditions. We propose a σ-bond metathesis mechanism in which an Fe-H intermediate is postulated to be a key reactive species.
- Tamang, Sem Raj,Findlater, Michael
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p. 12857 - 12862
(2017/12/08)
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- Cascade engineered synthesis of 2-ethyl-1-hexanol from n-butanal and 2-methyl-1-pentanol from n-propanal using combustion synthesized Cu/Mg/Al mixed metal oxide trifunctional catalyst
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2-Ethyl-1-hexanol (2-EH) is a commercially important chemical that requires cost effective catalytic processes for synthesis. The cascade engineered synthesis of 2-EH was done in a single pot from n-butanal using solventless conditions with trifunctional mixed metal oxide containing 5% Cu and Mg/Al ratio of 3. This trifunctional catalyst was made by combustion synthesis technique which resulted in a porous network with narrow pore size distribution. The catalyst was characterized before and after reuse by FTIR, XRD, SEM, TEM, CO2-TPD, NH3-TPD, TPR, TGA and nitrogen BET analysis. The kinetics of reaction and selectivity profile of 2-EH are reported. The work was extended to one pot cascade engineered synthesis of 2-methyl-1-pentanol (2-MP) from n-propanal using the same catalyst. There was a significant effect of molecular size on rate of reaction and selectivity of the product. This is the first ever report on the one pot synthesis of 2-MP from n-propanal.
- Patankar, Saurabh C.,Yadav, Ganapati D.
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p. 223 - 233
(2017/06/21)
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- Cobalt- and Iron-Catalyzed Isomerization-Hydroboration of Branched Alkenes: Terminal Hydroboration with Pinacolborane and 1,3,2-Diazaborolanes
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The synthesis and characterization of a series of structurally varied N-phosphinoamidinate-ligated cobalt complexes is described, along with the successful application of these and a related iron complex as precatalysts in the isomerization-hydroboration of terminal, geminal, and internal alkenes. These reactions proceed under mild conditions (23-65 °C), at relatively low base-metal loadings (1-5 mol %), typically without cosolvent, and with high terminal hydroboration selectivity across a broad spectrum of branched alkenes. With some of the alkene substrates examined, the N-phosphinoamidinate-ligated precatalysts employed herein are shown to provide alternative terminal selectivity versus other previously reported precatalyst classes for such transformations. Reports of terminal-selective metal-catalyzed alkene isomerization-hydroboration disclosed thus far in the literature employ pinacolborane (HBPin); while effective in the system herein, we also report the first examples of such transformations employing either 1,3-dimethyl-1,3-diaza-2-boracyclopentane or benzo-1,3,2-diazaborolane. The application of these 1,3,2-diazaborolanes in place of HBPin in some instances enables novel terminal selectivity in the isomerization-hydroboration of branched alkenes.
- Ogawa, Takahiko,Ruddy, Adam J.,Sydora, Orson L.,Stradiotto, Mark,Turculet, Laura
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supporting information
p. 417 - 423
(2017/04/26)
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- Triiodide-Mediated δ-Amination of Secondary C?H Bonds
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The Cδ?H amination of unactivated, secondary C?H bonds to form a broad range of functionalized pyrrolidines has been developed by a triiodide (I3?)-mediated strategy. By in situ 1) oxidation of sodium iodide and 2) sequestration of the transiently generated iodine (I2) as I3?, this approach precludes undesired I2-mediated decomposition which can otherwise limit synthetic utility to only weak C(sp3)?H bonds. The mechanism of this triiodide-mediated cyclization of unbiased, secondary C(sp3)?H bonds, by either thermal or photolytic initiation, is supported by NMR and UV/Vis data, as well as intercepted intermediates.
- Wappes, Ethan A.,Fosu, Stacy C.,Chopko, Trevor C.,Nagib, David A.
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supporting information
p. 9974 - 9978
(2016/08/16)
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- Asymmetric hydrogenation of allylic alcohols using ir?N,P-Complexes
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In this study, a series of γ,γ-disubstituted and β,γ-disubstituted allylic alcohols were prepared and successfully hydrogenated using suitable N,P-based Ir complexes. High yields and excellent enantioselectivities were obtained for most of the substrates studied. This investigation also revealed the effect of the acidity of the N,P?Ir-complexes on the acid-sensitive allylic alcohols. DFT ΔpKa calculations were used to explain the effect of the N,P-ligand on the acidity of the corresponding Ir-complex. The selectivity model of the reaction was used to accurately predict the absolute configuration of the hydrogenated alcohols.
- Li, Jia-Qi,Liu, Jianguo,Krajangsri, Suppachai,Chumnanvej, Napasawan,Singh, Thishana,Andersson, Pher G.
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p. 8342 - 8349
(2018/05/23)
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- PROCESSES FOR THE SYNTHESIS OF CHIRAL 1-ALKANOLS
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The invention relates to highly enantioselective processes for the synthesis of chiral 1-alkanols via Zr-catalyzed asymmetric carboalumination of alkenes.
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Paragraph 0214; 0215; 0222; 0223
(2016/12/01)
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- PROCESSES FOR THE SYNTHESIS OF CHIRAL 1-ALKANOLS
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The invention relates to highly enantioselective processes for the synthesis of chiral 1-alkanols via Zr-catalyzed asymmetric carboalumination of alkenes.
- -
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Paragraph 00110; 00114
(2015/07/23)
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- Synthesis, structure, and bonding properties of ruthenium complexes possessing a boron-based pbp pincer ligand and their application for catalytic hydrogenation
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In addition to our previous works for PBP-pincer metal complexes, four PBP-pincer Ru complexes, [PBP]Ru(Cl)(CO) (2), [PBP]Ru(CO)(2-BH4) (3), [PBP](-H)2Ru(OAc-2O) (4), and [PBP](-H)2Ru(2-BH4) (5) were synthesized. All the obtained complexes were characterized by NMR and IR spectroscopy, X-ray crystallography, elemental analysis, and DFT calculation with AIM analysis. Through the structural analysis, two types of interaction between boron atoms and ruthenium atoms in 3-5 were revealed. One is the typical two-center-two-electron bond between the boron atom of the PBP ligand and the Ru atom, associated with bridging hydride ligand(s) on the Ru(IV) center. The other is an ionic interaction between the Ru fragment and the tetrahydroborate anion. On comparison of the structural features, vibrational analysis, NBO analysis, and AIM analysis of the obtained compounds with those of the previously reported complexes having "similar" interactions among B, H, and Ru atoms, the interactions in 4 and 5 were proven to be different from that previously reported. The obtained complexes 3-5 were applied as catalysts for the hydrogenation of aldehyde. Complex 5 showed the highest catalytic activity and widest range of substrate scope. Two mechanisms for the catalytic cycle were proposed with an initial dissociation of BH3 or anionic ligand, according to the control experiments.
- Miyada, Takuma,Huang Kwan, Enrique,Yamashita, Makoto
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p. 6760 - 6770
(2015/02/19)
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- Rhodium-catalyzed homogeneous reductive amidation of aldehydes
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The catalytic reductive amidation of an aldehyde (hexanal) with an amide (acetamide) is reported. Apart from the desired N-hexylacetamide, the two isomeric unsaturated intermediates as well as hexanol are produced together with higher mass products that arise from aldol condensation and diamide coupling of the aldehyde. Screening of different catalyst precursor salts, ligands and reaction conditions led to the finding that the catalytic system based on the (cyclooctadiene)rhodium chloride dimer, [Rh(cod)Cl]2, in combination with the ligand xantphos and an acid co-catalyst results in high selectivity for the desired product. Under optimized conditions nearly full conversion is reached with high selectivity to the desired N-alkylamide and with a very high N-alkylamide/alcohol ratio, while producing only small amounts of by-products. The scope of the reaction has been investigated using different amides as well as aldehydes; the results show the general applicability of this novel reaction, but with electron-withdrawing amides the selectivity to N-alkylamide is lower. NMR studies showed that the nucleophilic addition of acetamide to hexanal is acid catalyzed, forming N-(1-hydroxyhexyl)acetamide in equilibrium with both hexanal and the dehydrated unsaturated imides. A catalytic mechanism is proposed in which a strong acid such as HOTs acts as a co-catalyst by establishing a rapid chemical equilibrium between the aldehyde, acetamide and the intermediates. Furthermore, it is proposed that the presence of acid causes a change in catalytic species, enabling a cationic Rh/xantphos hydrogenation catalyst to selectively hydrogenate the intermediates to N-hexylacetamide in the presence of hexanal. Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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supporting information
p. 717 - 733
(2013/04/23)
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- Chemo- and regioselective homogeneous rhodium-catalyzed hydroamidomethylation of terminal alkenes to N-alkylamides
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A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through catalytic hydroamidomethylation with 1-pentene and acetamide as model substrates. For appropriate catalyst performance, it appears to be essential that catalytic amounts of a strong acid promoter, such as p-toluenesulfonic acid (HOTs), as well as larger amounts of a weakly acidic protic promoter, particularly hexafluoroisopropyl alcohol (HORF) are applied. Apart from the product N-1-hexylacetamide, the isomeric unsaturated intermediates, hexanol and higher mass byproducts, as well as the corresponding isomeric branched products, can be formed. Under optimized conditions, almost full alkene conversion can be achieved with more than 80 % selectivity to the product N-1-hexylamide. Interestingly, in the presence of a relatively high concentration of HORF, the same catalyst system shows a remarkably high selectivity for the formation of hexanol from 1-pentene with syngas, thus presenting a unique example of a selective rhodium-catalyzed hydroformylation-hydrogenation tandem reaction under mild conditions. Time-dependent product formation during hydroamidomethylation batch experiments provides evidence for aldehyde and unsaturated intermediates; this clearly indicates the three-step hydroformylation/condensation/hydrogenation reaction sequence that takes place in hydroamidomethylation. One likely role of the weakly acidic protic promoter, HORF, in combination with the strong acid HOTs, is to establish a dual-functionality rhodium catalyst system comprised of a neutral rhodium(I) hydroformylation catalyst species and a cationic rhodium(III) complex capable of selectively reducing the imide and/or ene-amide intermediates that are in a dynamic, acid-catalyzed condensation equilibrium with the aldehyde and amide in a syngas environment. Taking control: A rhodium/xantphos homogeneous catalyst system has been developed for direct chemo- and regioselective mono-N-alkylation of primary amides with 1-alkenes and syngas through the new catalytic hydroamidomethylation reaction (see picture). Copyright
- Raoufmoghaddam, Saeed,Drent, Eite,Bouwman, Elisabeth
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p. 1759 - 1773
(2013/10/21)
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- SYNTHESIS OF HIGH CALORIC FUELS AND CHEMICALS
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In one embodiment, the present application discloses methods to selectively synthesize higher alcohols and hydrocarbons useful as fuels and industrial chemicals from syngas and biomass. Ketene and ketonization chemistry along with hydrogenation reactions are used to synthesize fuels and chemicals. In another embodiment, ketene used to form fuels and chemicals may be manufactured from acetic acid which in turn can be synthesized from synthesis gas which is produced from coal, biomass, natural gas, etc.
- -
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Paragraph 00109
(2013/05/23)
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- From olefins to alcohols: Efficient and regioselective ruthenium-catalyzed domino hydroformylation/reduction sequence
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Exploring the alternatives: Ruthenium imidazoyl phosphine complexes catalyze the domino hydroformylation/reduction of alkenes to alcohols in good yields and with good selectivities (see scheme). Linear aliphatic alcohols are synthesized under reaction conditions typically used in industrial hydroformylations. Copyright
- Fleischer, Ivana,Dyballa, Katrin Marie,Jennerjahn, Reiko,Jackstell, Ralf,Franke, Robert,Spannenberg, Anke,Beller, Matthias
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supporting information
p. 2949 - 2953
(2013/04/10)
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- Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
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α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
- Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
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p. 10609 - 10616
(2012/11/07)
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- Metathesis-mediated synthesis of (R)-10-Methyl-2-tridecanone, the southern corn rootworm pheromone
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(R)-10-Methyl-2-tridecanone, the female sex pheromone of the southern corn rootworm (Diabrotica undecimpunctata howardi Barber), was synthesized in 9 steps from methyl (S)-3-hydroxy-2-methylpropanoate in a 15.7% overall yield. Olefin cross metathesis between (R)-6-methyl-1-nonene and 5-hexen-2-one employing Grubbs' first-generation catalyst was the key step of the synthesis.
- Shikichi, Yasumasa,Moriy, Kenji
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experimental part
p. 407 - 409
(2012/08/13)
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- Tumescenamide C, an antimicrobial cyclic lipodepsipeptide from Streptomyces sp.
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Tumescenamide C, a new cyclic lipodepsipeptide, was isolated from a culture broth of an actinomycete Streptomyces sp. KUSC-F05. Tumescenamide C was a congener of tumescenamides A and B, representing a sixteen-membered ring system, consisting of two proteinogenic and three non-proteinogenic amino acids, to which a methyl-branched fatty acid was attached. The planar structure was determined by spectroscopic analysis, while its absolute stereochemistry was determined by chemical degradation and asymmetric synthesis. Tumescenamide C exhibited antimicrobial activity with high selectivity against Streptomyces species.
- Kishimoto, Shinji,Tsunematsu, Yuta,Nishimura, Shinichi,Hayashi, Yutaka,Hattori, Akira,Kakeya, Hideaki
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experimental part
p. 5572 - 5578
(2012/09/08)
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- PROCESS INCLUDING HYDROGENOLYSIS OF BIOMASS FOLLOWED BY DEHYDROGENATION AND ALDOL CONDENSATION FOR PRODUCING ALKANES
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A method comprises providing a bio-based feedstock; contacting the bio-based feedstock with a solvent in a hydrolysis reaction to form an intermediate stream comprising carbohydrates; contacting the intermediate stream with an aqueous phase reforming catalyst to form a plurality of oxygenated intermediates, wherein a first portion of the oxygenated intermediates are recycled to form the solvent; and contacting at least a second portion of the oxygenated intermediates with a condensation catalyst comprising a base functionality to form a fuel blend.
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Page/Page column 34-37
(2011/12/02)
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- Chemical development of an α2δ ligand, (3 S,5 R)-3-(Aminomethyl)-5-methyloctanoic acid
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Three synthetic approaches, suitable for the large scale manufacture of the α2δ-ligand, (3S,5R)-3-(aminomethyl)-5-methyloctanoic acid 3, have been evaluated. The selected seven step manufacturing process has then been optimized and used to deliver over 20 kg of API; salient features of the synthesis include the use of 4,4,4-trimethoxybutyronitrile as an efficient four carbon amino acid equivalent. Highly selective kinetic resolution of the C3 stereocentre was accomplished via diastereoselective hydrolysis of a cyanoester intermediate using Amano Lipase PS-SD. Extensive process optimisation of the route starting from (R)-2-methylpentanol, led to significant improvements through telescoping, with less than 62 kg of solvent being needed to produce 1 kg of API.
- Murtagh, Lorraine,Dunne, Catherine,Gabellone, Gino,Panesar, Niamh J.,Field, Stuart,Reeder, Lisa M.,Saenz, James,Smith, George P.,Kissick, Kyle,Martinez, Carlos,Van Alsten, John G.,Evans, Margaret C.,Franklin, Lloyd C.,Nanninga, Thomas,Wong, John
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experimental part
p. 1315 - 1327
(2012/01/12)
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- Iridium-catalyzed asymmetric hydrogenation of unfunctionalized, trialkyl-substituted olefins
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Chiral iridium complexes with bicyclic pyridine-based N,P ligands have emerged as efficient catalysts for the enantioselective hydrogenation of unfunctionalized trialkyl-substituted olefins. Optimization of the reaction conditions by variation of the solvent, pressure, and temperature led to enantiomeric excesses of up to 99%. Three pure alkenes, (E)-2-cyclohexyl-2- butene and (E)- and (Z)-3,4-dimethyl-2-pentene were converted into the corresponding chiral alkanes with 97%, 94%, and 93% ee, respectively. Hydrogenation of the three C=C bonds of both α- and γ-tocotrienyl acetate led to α- and γ-tocopheryl acetate with very high diastereoselectivity. The same catalysts were successfully applied in the hydrogenation of trisubstituted alkenes with a carboxylic ester or a keto group in the γ position. This reaction was used as a key step in a highly enantioselective synthesis of the pheromone of the caddisfly Hesperophylax occidentalis. The hydrogenation of a structurally analogous allylic alcohol also gave high enantioselectivities. Unfunctionalized trialkyl-substituted olefins are hydrogenated with high efficiency and excellent enantioselectivity using iridium complexes derived from chiral N,P ligands. In this way, pharmaceutically interesting and industrially relevant compounds with chiral alkyl fragments are easily accessible with high diastereo- and enantioselectivities. Copyright
- Wang, Aie,Fraga, Rui P. A.,Hoermann, Esther,Pfaltz, Andreas
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p. 599 - 606
(2011/10/12)
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- COMPOUNDS FOR INHIBITING WIP1, PRODRUGS AND COMPOSITIONS THEREOF, AND RELATED METHODS
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The invention provides compounds useful in inhibiting the activity of a Wip1 protein in a cell as well as prodrugs thereof, related methods of use and compositions which include the aforesaid compounds and prodrugs thereof. The compounds comprise a ring structure having at least five functional groups bonded thereto, wherein each functional group is bonded to a different ring atom, and wherein the at least five functional groups comprise: (a) first (R1) and second (R3) moieties each comprising a phosphate group wherein these first and second moieties are separated by at least one ring atom; (b) first (R2) and second (R4) hydrophobic groups, wherein the first and second hydrophobic groups are separated by at least one ring atom, and wherein the first hydrophobic group is bonded to a ring atom located between the ring atoms to which the first (R1) and second (R2) moieties are bonded; and an amide or carboxylic acid (R5).
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Page/Page column 38-39
(2009/04/25)
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- Colloidal palladium nanoparticles with in situ H2: Reducing system for ,-unsaturated carbonyl compounds
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A new reducing system comprising Pd(OAc)2 and NaBH4 in methanol to generate palladium nanoparticles has been efficiently utilized to reduce a variety of unsaturated carbonyl compounds. These were reduced to their corresponding saturated alcohols and fully saturated compounds in selected cases. This protocol presents alternative and mild reaction conditions for reduction.
- De Castro, Kathlia A.,Oh, Seungchan,Yun, Jongchan,Lim, Jin Kyu,An, Gwangil,Kim, Dong Kook,Rhee, Hakjune
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experimental part
p. 3509 - 3520
(2009/12/05)
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- METHOD FOR SYNTHESIS OF CHEMICAL INDUSTRIAL RAW MATERIAL OR FUEL COMPOSITION
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The present invention is to provide a novel method for manufacturing various organic compounds from 2 or more kinds of alcohol, or 1 kind of alcohol having 3 or more carbon atoms. It is a method for synthesizing 1 kind of, or 2 or more kinds of organic compounds comprising allowing 2 or more kinds of alcohol or 1 kind of alcohol having 3 or more carbon atoms to contact hydroxyapatite (except those supporting metal catalysts or metal ion catalysts acting on alcohol).
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Page/Page column 15
(2009/08/14)
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- Design, synthesis, and biological activity of isophthalic acid derivatives targeted to the C1 domain of protein kinase C
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Protein kinase C (PKC) is a widely studied molecular target for the treatment of cancer and other diseases. We have approached the issue of modifying PKC function by targeting the C1 domain in the regulatory region of the enzyme. Using the X-ray crystal structure of the PKC δ C1b domain, we have discovered conveniently synthesizable derivatives of dialkyl 5-(hydroxymethyl)isophthalate that can act as potential C1 domain ligands. Structure-activity studies confirmed that the important functional groups predicted by modeling were indispensable for binding to the C1 domain and that the modifications of these groups diminished binding. The most promising compounds were able to displace radiolabeled phorbol ester ([3H]PDBu) from PKC α and δ at Ki values in the range of 200-900 nM. Furthermore, the active isophthalate derivatives could modify PKC activation in living cells either by inducing PKC-dependent ERK phosphorylation or by inhibiting phorbol-induced ERK phosphorylation. In conclusion, we report here, for the first time, that derivatives of isophthalic acid represent an attractive novel group of C1 domain ligands that can be used as research tools or further modified for potential drug development.
- Af Genn?s, Gustav Boije,Talman, Virpi,Aitio, Olli,Ekokoski, Elina,Finel, Moshe,Tuominen, Raimo K.,Yli-Kauhaluoma, Jari
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supporting information; scheme or table
p. 3969 - 3981
(2010/01/16)
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- Asymmetric bioreduction of C=C bonds using enoate reductases OPR1, OPR3 and YqjM: Enzyme-based stereocontrol
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Three cloned enoate reductases from the "old yellow enzyme" family of flavoproteins were investigated in the asymmetric bioreduction of activated alkenes. 12-Oxophytodienoate reductase isoenzymes OPR1 and OPR3 from Lycopersicon esculentum (tomato), and YqjM from Bacillus subtilis displayed a remarkably broad substrate spectrum by reducing α,β-unsaturated aldehydes, ketones, maleimides and nitroalkenes. The reaction proceeded with absolute chemoselectivity-only the conjugated C=C bond was reduced, while isolated olefins and carbonyl groups remained intact-with excellent stereoselectivities (ees up to >99%). Upon reduction of a nitroalkene, the stereochemical outcome could be determined via choice of the appropriate enzyme (OPR1 versus OPR3 or YqjM), which furnished the corresponding enantiomeric nitroalkanes in excellent ee. Molecular modelling suggests that this "enzyme-based stereocontrol" is caused by subtle differences within the active site geometries.
- Hall, Melanie,Stueckler, Clemens,Ehammer, Heidemarie,Pointner, Eva,Oberdorfer, Gustav,Gruber, Karl,Hauer, Bernard,Stuermer, Rainer,Kroutil, Wolfgang,Macheroux, Peter,Faber, Kurt
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experimental part
p. 411 - 418
(2009/04/10)
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- Zirconium-catalyzed asymmetric carboalumination of alkenes: ZACA-lipase-catalyzed acetylation synergy
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ZACA-lipase-catalyzed acetylation tandem reactions provide highly efficient and selective routes to either (R)- or (S)-2-methyl-1-alkanols, making, for the first time, the ZACA-based asymmetric synthesis of 2-methyl-1-alkanols widely applicable and satisfactory.
- Huang, Zhihong,Tan, Ze,Novak, Tibor,Zhu, Gangguo,Negishi, Ei-Ichi
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p. 539 - 545
(2008/02/08)
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- RuHCl(CO)(PPh3)3-catalyzed reductive dimerization of α,β-unsaturated aldehydes leading to α-hydroxymethyl ketones
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The reductive dimerization α,β-unsaturated aldehydes to give saturated ketones was achieved using RuHCl(CO)(PPh3)3 as a catalyst in the presence of secondary alcohols as hydrogen source. The reaction is likely to proceed via the hydroruthenation of α,β-unsaturated aldehydes followed by aldol reaction of the resultant ruthenium enolates with α,β-unsaturated aldehydes to give unsaturated α-hydroxymethyl ketones, which undergo transfer hydrogenation to give α-hydroxymethyl ketones. Georg Thieme Verlag Stuttgart.
- Doi, Takashi,Fukuyama, Takahide,Minamino, Satoshi,Ryu, Ilhyong
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p. 3013 - 3016
(2008/02/12)
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- On water and in air: Fast and highly chemoselective transfer hydrogenation of aldehydes with iridium catalysts
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(Chemical Equation Presented) Water as solvent: A fast, selective, and high-yielding transfer hydrogenation of a wide range of aldehydes is achieved using IrIII catalysts containing simple ethylene-diamine (en) ligands (see scheme; Ts = p-toluenesulfonyl, TOF = turnover frequency). This procedure is suitable for aldehydes with a wide range of functional groups.
- Wu, Xiaofeng,Liu, Jianke,Li, Xiaohong,Zanotti-Gerosa, Antonio,Hancock, Fred,Vinci, Daniele,Ruan, Jiwu,Xiao, Jianliang
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p. 6718 - 6722
(2007/10/03)
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- New chiral synthons for efficient introduction of bispropionates via stereospecific oxonia-cope rearrangements
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Compounds 1 and 2 are novel synthons for bispropionate synthesis, undergoing stereospecific Lewis acid-catalyzed transfer of the bispropionate unit with a variety of aldehydes, including α-chiral aldehydes. Thus 1 leads to the E-alkene bispropionate 3 with anti-stereochemistry, whereas diastereomer 2 gives the Z-alkene product 4, under mild conditions and with complete stereospecificity. The efficacy of this methodology is demonstrated in a short synthesis of invictolide beginning with 2 and (R)-2-methylpentanal. Copyright
- Chen, Yi-Hung,McDonald, Frank E.
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p. 4568 - 4569
(2007/10/03)
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- Transfer hydrogenation of aldehydes with 2-propanol and Raney nickel
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Raney nickel in refluxing 2-propanol containing a trace of HCl is an effective catalytic system for the reduction of aldehydes to primary alcohols. Copyright Taylor & Francis, Inc.
- Mebane, Robert C.,Mansfield, Amanda J.
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p. 3083 - 3086
(2007/10/03)
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