- Binuclear complexes for aerobic oxidation of primary alcohols and carbohydrates
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The influence of electron-donating and electron-accepting properties of three pentadentate ligands was determined in connection with the aerobic oxidation ability of the corresponding binuclear copper(II) complexes for benzyl and allyl alcohols; additionally, the catalytic performance of their palladium and platinum analogs was characterized under comparable conditions. Quantitative aerobic oxidation of benzyl alcohol at 40 °C was achieved with a binuclear copper(II) complex - TEMPO catalyst in 2.5 h, while the regioselective aerobic oxidation of underivatized methyl-β-d-glucopyranoside was accomplished in about 35% yield at 60 °C after 24 h.
- Striegler, Susanne,Dunaway, Natasha A.,Gichinga, Moses G.,Milton, Lisa K.
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- Synthesis of regioselectively deuterated cyclopropanes
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A regioselective synthesis of deuterated aliphatic cyclopropanes has been developed to furnish labeled substrates for gas-phase ion-molecule reaction studies.
- Duffault, Jean-Marc,Hanoteau, Pascal,Parrilla, Alfredo,Einhorn, Jacques
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Read Online
- Palladium-Catalyzed Enantioselective Redox-Relay Heck Alkynylation of Alkenols To Access Propargylic Stereocenters
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An enantioselective redox-relay Heck alkynylation of di- and trisubstituted alkenols to construct propargylic stereocenters is disclosed using a new pyridine oxazoline ligand. This strategy allows direct access to chiral β-alkynyl carbonyl compounds employing allylic alcohol substrates in contrast to more traditional conjugate addition methods.
- Chen, Zhi-Min,Nervig, Christine S.,DeLuca, Ryan J.,Sigman, Matthew S.
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supporting information
p. 6651 - 6654
(2017/05/29)
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- Characterization of the monolignol oxidoreductase AtBBE-like protein 15 L182V for biocatalytic applications
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Monolignol oxidoreductases from the berberine bridge enzyme-like (BBE-like) protein family (pfam 08031) catalyze the oxidation of monolignols to the corresponding aldehydes. In this report, we explore the potential of a monolignol oxidoreductase from Arabidopsis thaliana (AtBBE-like protein 15) as biocatalyst for oxidative reactions. For this study we employed a variant with enhanced reactivity towards oxygen, which was obtained by a single amino acid exchange (L182V). The pH and temperature optima of the purified AtBBE-like protein 15 L182V were determined as well as the tolerance toward organic co-solvents; furthermore the substrate scope was characterized. The enzyme has a temperature optimum of 50 °C and retains more than 50% activity between pH 5 and pH 10 within 5 min. The enzyme shows increased activity in the presence of various co-solvents (10–50% v/v), including acetonitrile, 2-propanol, 1,4-dioxane, and dimethyl sulfoxide. Primary benzylic and primary or secondary allylic alcohols were accepted as substrates. The enantioselectivity E in the oxidation of secondary alcohols was good to excellent (E>34 to?>200).
- Pils, Sabine,Schnabl, Kordula,Wallner, Silvia,Daniel, Bastian,Macheroux, Peter,Kljajic, Marko,Kupresanin, Nina,Breinbauer, Rolf,Fuchs, Michael,Rocha, Raquel,Schrittwieser, Joerg H.,Kroutil, Wolfgang
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- Method for preparing Z-isomer by E-isomer of alpha, beta-nonsaturated carbonyl compound
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The invention provides a method for preparing a Z-isomer by an E-isomer of an alpha, beta-nonsaturated carbonyl compound. The method uses nitrogen-containing chiral binaphthol phosphoramidite to prepare a catalyst, under mild reaction condition, the E-isomer of the alpha, beta-nonsaturated carbonyl compound is efficiently conversed to the Z-isomer. The method is especially suitable for preparing neral through isomerization of partial geranial in a citral split residual material, the citral with mol ratio of the obtained geranial to neral being 1:1 can be reused for splitting the neral, raw material utilization rate is increased, and the cost is reduced.
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Paragraph 0054; 0055
(2017/04/29)
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- Copper(I)/ABNO-catalyzed aerobic alcohol oxidation: Alleviating steric and electronic constraints of Cu/TEMPO catalyst systems
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Cu/TEMPO catalyst systems promote efficient aerobic oxidation of sterically unhindered primary alcohols and electronically activated substrates, but they show reduced reactivity with aliphatic and secondary alcohols. Here, we report a catalyst system, consisting of (MeObpy)CuI(OTf) and ABNO (MeObpy =4,4′-dimethoxy-2,2′-bipyridine; ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl), that mediates aerobic oxidation of all classes of alcohols, including primary and secondary allylic, benzylic, and aliphatic alcohols with nearly equal efficiency. The catalyst exhibits broad functional group compatibility, and most reactions are complete within 1 h at room temperature using ambient air as the source of oxidant.
- Steves, Janelle E.,Stahl, Shannon S.
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supporting information
p. 15742 - 15745
(2013/11/06)
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- Highly practical copper(I)/TEMPO catalyst system for chemoselective aerobic oxidation of primary alcohols
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Aerobic oxidation reactions have been the focus of considerable attention, but their use in mainstream organic chemistry has been constrained by limitations in their synthetic scope and by practical factors, such as the use of pure O2 as the oxidant or complex catalyst synthesis. Here, we report a new (bpy)CuI/TEMPO catalyst system that enables efficient and selective aerobic oxidation of a broad range of primary alcohols, including allylic, benzylic, and aliphatic derivatives, to the corresponding aldehydes using readily available reagents, at room temperature with ambient air as the oxidant. The catalyst system is compatible with a wide range of functional groups and the high selectivity for 1° alcohols enables selective oxidation of diols that lack protecting groups.
- Hoover, Jessica M.,Stahl, Shannon S.
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supporting information; experimental part
p. 16901 - 16910
(2011/12/04)
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- Copper on boehmite: A simple, selective, efficient and reusable heterogeneous catalyst for oxidation of alcohols with periodic acid in water at room temperature
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Oxidation of various aliphatic, aromatic, alicyclic, benzylic and allylic alcohols to corresponding carbonyl compounds is studied in water at room temperature over copper on boehmite [Cu/AlO(OH)] catalyst which is prepared from CuCl2·2H2O, pluronic P123 and Al(O-sec-Bu) 3. The prepared catalyst was characterized by HR-TEM, SEM-EDX and IR spectroscopy. The reaction conditions for catalytic oxidation of alcohols are optimized with different mole ratio, solvents, and oxidants using 1-phenylethanol system as a model. The scope of the reaction is extended to various types of alcohols. Chemoselectivity, heterogeneity and reusability tests were performed. The use of water as a solvent at room temperature makes the reaction interesting from both an economic and environmental point of view.
- Babu, S. Ganesh,Priyadarsini, P. Aruna,Karvembu
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experimental part
p. 218 - 224
(2011/11/05)
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- Biooxidation of Primary Alcohols to Aldehydes through Hydrogen Transfer Employing Janibacter terrae
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Chemoselective oxidations still represent a challenge for chemists. Lyophilized cells of Janibacter terrae were employed for the chemoselective oxidation of primary alcohols to the corresponding aldehydes by hydrogen transfer with the use of acetaldehyde as the hydrogen acceptor. Secondary alcohol moieties were transformed at a much slower rate. The substrate spectrum encompasses substituted benzyl alcohols, whereby substrates with a substituent in the meta position were well tolerated, whereas only very small substituants were tolerated in the ortho position. Furthermore, nalkanols and allylic alcohols were transformed with good conversions. The biocatalyst was compatible with DMSO as a water miscible organic solvent up to 30 % v/v.
- Orbegozo, Thomas,De Vries, Johannes G.,Kroutil, Wolfgang
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experimental part
p. 3445 - 3448
(2010/09/05)
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- Oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds with aqueous hydrogen peroxide under organic solvent-free conditions
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Allylic alcohols are chemoselectively oxidized to α,β- unsaturated carbonyl compounds in high yield with aqueous H2O 2 in the presence of Pt black catalyst under organic solvent-free conditions. The catalyst is easily recyclable and effective for at least 7 cycles. The Royal Society of Chemistry.
- Kon, Yoshihiro,Usui, Yoko,Sato, Kazuhiko
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p. 4399 - 4400
(2008/04/01)
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- Regioselective alkene carbon-carbon bond cleavage to aldehydes and chemoselective alcohol oxidation of allylic alcohols with hydrogen peroxide catalyzed by [cis-Ru(II)(dmp)2(H2O)2] 2+ (dmp = 2,9-dimethylphenanthroline)
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(Chemical Equation Presented) [cis-Ru(II)(dmp)2(H 2O)2]2+ (dmp = 2,9-dimethylphenanthroline) was found to be a selective oxidation catalyst using hydrogen peroxide as oxidant. Thus, primary alkenes were very efficiently oxidized via direct carbon-carbon bond cleavage to the corresponding aldehydes as an alternative to ozonolysis. Secondary alkenes were much less reactive, leading to regioselective oxidation of substrates such as 4-vinylcyclohexene and 7-methyl-1,6-octadiene at the terminal position. Primary allylic alcohols were chemoselectively oxidized to the corresponding allylic aldehydes, e.g., geraniol to citral.
- Kogan, Vladimir,Quintal, Miriam M.,Neumann, Ronny
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p. 5039 - 5042
(2007/10/03)
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- A convenient one-pot PCC oxidation-Wittig reaction of alcohols
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A simple one-pot process for the PCC oxidation of alcohols followed by in situ trapping of the aldehyde with a Wittig reagent is described.
- Bressette, Andrew R.,Glover IV, Louis C.
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p. 738 - 740
(2007/10/03)
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- Mild and selective oxidation of alcohols and deoximation of oximes over supported quinolinium fluorochromate
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Quinolinium fluorochromate supported over silica gel selectively brings about the oxidation of a wide variety of alcohols and oxidative deoximation of certain aldoximes and ketoximes to the corresponding carbonyl compounds in good yield. The reagent selectively oxidises primary hydroxyl group in the presence of secondary hydroxyl group. The selectivity is also exhibited in the oxidation of axial hydroxyl group of the cis-4-t-butyl cyclohexanol in preference to equitorial hydroxyl group. Further the reagent is stable even after a period of twelve weeks of its storage.
- Rajkumar, G. Abraham,Sivamurugan,Arabindoo, Banumathi,Murugesan
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p. 936 - 946
(2007/10/03)
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- Polyfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents
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[Matrix presented] Polyfluorinated quaternary ammonium cations, [CF 3(CF2)7(CH2)3] 3CH3N+ (RFN+), were synthesized and used as countercations for the [WZnM2(H 2O)2(ZnW9O34)2] 12- (M = Mn(II), Zn(II)) polyoxometalate. The (RFN +)12[WZnM2(H20)2 (ZnW9O34)2] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected by both the hydrophobicity of the solvent and the substrate.
- Maayan, Galia,Fish, Richard H.,Neumann, Ronny
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p. 3547 - 3550
(2007/10/03)
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- Total Synthesis and Biological Evaluation of (-)Apicularen A and Analogues Thereof
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Apicularen A (1) and related benzolactone acylenamines belong to a growing class of novel natural products possessing highly cytotoxic properties. The challenging structure of 1 includes a 10-membered macrolactone ring, a tetrahydropyran system, an o,m-substituted phenol and a doubly unsaturated acyl group attached on the side chain enamine functionality. The total synthesis of apicularen A described herein involves a strategy equivalent to its proposed biosynthesis and entails a reiterative two-step procedure featuring allylation and ozonolytic cleavage to grow the molecule's chain by one acetate unit at a time. The developed synthetic technology was applied to the construction of a series of apicularen A analogues whose biological evaluation established a set of structure-activity relationships in this new area of potential importance in cancer chemotherapy.
- Nicolaou,Kim, David W.,Baati, Rachid,O'Brate, Aurora,Giannakakou, Paraskevi
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p. 6177 - 6191
(2007/10/03)
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- Oxygen transfer from sulfoxides: Selective oxidation of alcohols catalyzed by polyoxomolybdates
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Benzylic, allylic, and aliphatic alcohols are oxidized to aldehydes and ketones in a reaction catalyzed by Keggin-type polyoxomolybdates, PVxMo(12-x)O40-(3+x) (x = 0, 2), with DMSO as a solvent. The oxidation of benzylic alcohols is quantitative within hours and selective, whereas that of allylic alcohols is less selective. Oxidation of aliphatic alcohols is slower but selective. Further mechanistic studies revealed that, for H3PMo12O40 as a catalyst and benzylic alcohols as substrates, the sulfoxide is in fact an oxygen donor in the reaction. Postulated reaction steps as determined from isotopelabeling experiments, kinetic isotope effects, and Hammett plots include (a) sulfoxide activation by complexation to the polyoxometalate and (b) oxygen transfer from the activated sulfoxide and elimination of water from the alcohol. The mechanism is supported by the reaction kinetics.
- Khenkin, Alexander M.,Neumann, Ronny
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p. 7075 - 7079
(2007/10/03)
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- A new non-metal heterogeneous catalyst for the activation of hydrogen peroxide: A perfluorinated ketone attached to silica for oxidation of aromatic amines and alkenes
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A silane functionalized by octafluoroacetophenone was polymerized by the sol-gel method to form an insoluble silicate with perfluoroketone pendants; the silicate was used as a heterogeneous catalyst for the activation of aqueous hydrogen peroxide and the oxidation of aromatic amines and alkenes.
- Neimann,Neumann
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p. 487 - 488
(2007/10/03)
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- Quinones as co-catalysts and models for the surface of active carbon in the phosphovanadomolybdate-catalyzed aerobic oxidation of benzylic and allyilic alcohols: Synthetic, kinetic, and mechanistic aspects
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Quinones have been considered as reactive compounds present on the surface of active carbon. Thus, the co-catalytic use of quinones combined with the phosphovanadomolybdate polyoxometalate, PV2Mo10O405-, has been studied as an analogue of the known PV2Mo10O405-/C catalyst in oxidative dehydrogenation reactions. From the synthetic point of view both biphasic the quinone (org)-Na5PV2Mo10O40 (aq) and monophasic quinone (org)4Q5PV2Mo10O40-(org) [4Q: (nC4H9)4N+] systems are effective for the selective oxidation of benzylic and allylic alcohols to their corresponding aldehydes. Kinetic measurements carried out on the model oxidative dehydrogenation of 4-methylbenzyl alcohol in the presence of p- chloranil, 4Q5PV2Mo10O40, and molecular oxygen showed that the reaction was non-elementary, although the 4-methylbenzyl alcohol oxydehydrogenation was the rate-determining step. ESR measurements showed the presence of the semiquinone of p-chloranil, probably as a complex with the polyoxometalate. This proposed complex was shown to be a more potent oxidant than p-chloranil. Thus, for the oxidation of 4-methoxytoluene the semiquinone complex was active, whereas p-chloranil alone was inactive. Beyond the importance of understanding quinone-phosphovanadomolybdate polyoxometalatecatalyzed reactions, insight gained from the formation of semiquinone active species can be applied for heterogeneous and aerobic oxidative transformations catalyzed by PV2Mo10O405- with carbon matrices as active supports.
- Neumann, Ronny,Khenkin, Alexander M.,Vigdergauz, Inga
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p. 875 - 882
(2007/10/03)
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- Microwave-assisted oxidation of saturated and unsaturated alcohols with t-butyl hydroperoxide and zeolites
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Under microwave irradiation 3? molecular sieves promote the oxidation of secondary (linear and cyclic) and benzylic alcohols to the corresponding carbonyl compounds by t-butyl hydroperoxide. Under the same conditions, α,β-unsaturated alcohols are converted into α,β-epoxyalcohols in regio- and diastereoselective way. Both oxidative processes can be performed under solvent-free conditions; however, epoxidation of allylic alcohols is found to proceed with more satisfactory efficiency in saturated aliphatic hydrocarbon (n-hexane or cyclohexane).
- Palombi, Laura,Bonadiesa, Francesco,Scettri, Arrigo
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p. 15867 - 15876
(2007/10/03)
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- Syntheses and NMR analyses of the eight geometric isomers of 3,6,8-dodecatrien-1-ol, subterranean termite trail pheromone
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Eight geometric isomers of 3,6,8-dodecatrien-1-ol 1, the trail-following pheromone of subterranean termites (Reticulitermes sp. Banks), were synthesized via a Wittig olefination reaction. The convergent syntheses of 1 consisted of a combination of two fragments, each containing an olefin with a fixed configuration, by formation of a third double bond to give a mixture of two geometric isomers. The mixtures of 1 were resolved by recycle high-performance liquid chromatography methods. 1H and 13C NMR peak assignments of the individual isomers were accomplished by homonuclear COSY, and one-bond CH correlation spectroscopy.
- Eya, Bryan K.,Otsuka, Toshikazu,Kubo, Isao,Wood, David L.
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p. 2695 - 2706
(2007/10/02)
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- Reactions with Phosphine Alkylenes, 44. A Further Synthesis of (Z)-α,β-Unsaturated Aldehydes
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Reaction of phosphorus ylides 4, especially such with electron donating groups R, with the glyoxal semiacetal 5 leads Z-stereospecifically to the formation of the acetals 3, which can be cleaved to the (Z)-α,β-unsaturated aldehydes 6.
- Bestmann, Hans Juergen,Ermann, Peter
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p. 3264 - 3266
(2007/10/02)
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