- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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- Method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene
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The invention discloses a method for preparing carboxylic acid by catalyzing aldehyde oxidation with N-heterocyclic carbene, and relates to the field of catalytic technology. The method comprises thefollowing steps: taking deionized water as a solvent and aldehyde as a reaction substrate, adding alkali into a reaction system, taking air as an oxidant and N-heterocyclic carbene as a catalyst required by the reaction, and carrying out catalytic oxidation on aldehyde at room temperature to 80 DEG C to generate a corresponding reaction product. The method has the beneficial effects that the N-heterocyclic carbene is used as the catalyst, no organic solvent is needed in the reaction process, the reaction process is green and safe, and the reaction yield is high.
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Paragraph 0043; 0094-0099; 0101-0106
(2020/11/25)
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- Replacement of an Indole Scaffold Targeting Human 15-Lipoxygenase-1 Using Combinatorial Chemistry
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Human 15-lipoxygenase-1 (15-LOX-1) belongs to the class of lipoxygenases, which catalyze oxygenation of polyunsaturated fatty acids, such as arachidonic and linoleic acid. Recent studies have shown that 15-LOX-1 plays an important role in physiological processes linked to several diseases such as airway inflammation disease, coronary artery disease, and several types of cancer such as rectal, colon, breast and prostate cancer. In this study, we aimed to extend the structural diversity of 15-LOX-1 inhibitors, starting from the recently identified indolyl core. In order to find new scaffolds, we employed a combinatorial approach using various aromatic aldehydes and an aliphatic hydrazide tail. This scaffold-hopping study resulted in the identification of the 3-pyridylring as a suitable replacement of the indolyl core with an inhibitory activity in the micromolar range (IC50=16±6 μm) and a rapid and efficient structure–activity relationship investigation.
- Prismawan, Deka,van der Vlag, Ramon,Guo, Hao,Dekker, Frank J.,Hirsch, Anna K. H.
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- Modified liquid–liquid interface cultivation system with floating microspheres and binder micro-pieces for slow-growing or unicellular microorganisms: Application to interfacial bioconversions with an actinomycete and yeasts
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Liquid–liquid interface bioreactor (L–L IBR) is a unique non-aqueous bioconversion system which comprises a hydrophobic organic solvent (upper phase), a fungal cells–floating microspheres (MS) layer (middle phase), and a liquid medium (lower phase). In this study, a modified L–L IBR with actinomycetes and yeasts was developed by using binder micro-pieces (BM) and estimated its availability through some bioconversions. This modified interface cultivation system was named a tacky liquid–liquid interface bioreactor (L–L IBRtac). After the detailed estimation of its characteristics, the system was applied to oxidation of citronellol to citronellal, 2-methylcyclohexanol to 2-methylcyclohexanone, and 2-octanol to 2-octanone with Rhodococcus hoagii NBRC 3730, oxidation of citronellal to citronellic acid with Candida viswanathii NBRC 10321, and transacetylation of citronellol by acetyl coenzyme A (acetyl-CoA) produced from glucose by Pichia kluyveri NBRC 1165. The accumulation of citronellal, 2-methylcyclohexanone, and 2-octanone reached 3.1 (16 days), 2.3 (12 days), and 32.9 g/l (12 days) in spite of strong biotoxicities of the substrates/products without collapse of a cells–MS–BM layer. On the other hand, 6.1 g/l of citronellic acid and 2.8 g/l of citronellyl acetate were produced from 5% citronellal and 10% citronellol for 12 days, respectively.
- Oda, Shinobu,Nakanishi, Mami,Ishikawa, Asako,Baba, Toshiki
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- Aerobic Photooxidative Synthesis of β-Alkoxy Monohydroperoxides Using an Organo Photoredox Catalyst Controlled by a Base
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Transition-metal-free synthesis of β-alkoxy monohydroperoxides via aerobic photooxidation using an acridinium photocatalyst was developed. This method enables the synthesis of some novel hydroperoxides. The peroxide source is molecular oxygen, which is cost-effective and atomically efficient. Magnesium oxide plays an important role as a base in the catalytic system.
- Asano, Yuya,Nagasawa, Yoshitomo,Yamaguchi, Eiji,Itoh, Akichika
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supporting information
p. 409 - 412
(2018/02/21)
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- Oxidative Transformations of Biosourced Alcohols Catalyzed by Earth-Abundant Transition Metals
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The catalytic acceptorless dehydrogenative oxidation of biosourced alcohols into carboxylic acid salts was achieved using earth-abundant Fe and Mn complexes that feature aliphatic PNP pincer ligands in good to excellent yields. The Fe derivatives were characterized by using 57Fe NMR spectroscopy. Mn pincer catalysts are catalytically more efficient than their Fe counterparts thanks to their robustness under basic conditions. Attempts to generate aldehydes from alcohols were not successful using the Fe and Mn species, but a commercially available Ru analogue achieves this transformation selectively under very mild conditions in the presence of a large excess of acetone as a hydrogen acceptor.
- Nguyen, Duc Hanh,Morin, Yohann,Zhang, Lei,Trivelli, Xavier,Capet, Frédéric,Paul, Sébastien,Desset, Simon,Dumeignil, Franck,Gauvin, Régis M.
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p. 2652 - 2660
(2017/07/28)
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- Catalytic Fehling's Reaction: An Efficient Aerobic Oxidation of Aldehyde Catalyzed by Copper in Water
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The first example of homogeneous copper-catalyzed aerobic oxidation of aldehydes is reported. This method utilizes atmospheric oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification.
- Liu, Mingxin,Li, Chao-Jun
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supporting information
p. 10806 - 10810
(2016/09/03)
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- γ-Lactone Synthesis via Palladium(II)-Catalyzed Lactonization of Unactivated Methylene C(sp3)-H Bonds
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A palladium(II)-catalyzed intramolecular lactonization of unactivated methylene C(sp3)-H bonds using PIP bidentate auxiliary is described. This method provides an efficient and concise pathway to synthesize functionalized γ-lactones.
- Liu, Bin,Shi, Bing-Feng
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supporting information
p. 2396 - 2400
(2016/09/28)
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- Nitrous Oxide as a Hydrogen Acceptor for the Dehydrogenative Coupling of Alcohols
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The oxidation of alcohols with N2O as the hydrogen acceptor was achieved with low catalyst loadings of a rhodium complex that features a cooperative bis(olefin)amido ligand under mild conditions. Two different methods enable the formation of either the corresponding carboxylic acid or the ester. N2 and water are the only by-products. Mechanistic studies supported by DFT calculations suggest that the oxygen atom of N2O is transferred to the metal center by insertion into the Rh-H bond of a rhodium amino hydride species, generating a rhodium hydroxy complex as a key intermediate.
- Gianetti, Thomas L.,Annen, Samuel P.,Santiso-Quinones, Gustavo,Reiher, Markus,Driess, Matthias,Grützmacher, Hansj?rg
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supporting information
p. 1854 - 1858
(2016/02/03)
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- Enzyme cascade reactions: Synthesis of furandicarboxylic acid (FDCA) and carboxylic acids using oxidases in tandem
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A one-pot tandem enzyme reaction using galactose oxidase M3-5 and aldehyde oxidase PaoABC was used to convert hydroxymethylfurfural (HMF) to the pure bioplastics precursor FDCA in 74% isolated yield. A range of alcohols was also converted to carboxylic acids in high yield under mild conditions.
- McKenna, Shane M.,Leimkühler, Silke,Herter, Susanne,Turner, Nicholas J.,Carnell, Andrew J.
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supporting information
p. 3271 - 3275
(2015/06/25)
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- Enantioselectivity of the bioconversion of chiral citronellal during the inhibition of wheat seeds germination
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Citronellal is one of the most prominent monoterpenes present in many essential oils. Low persistence of essential oils as bioherbicides has often been addressed because of the high volatility of these compounds. Bioconversion of citronellal by wheat seeds releases less aggressive and injurious compounds as demonstrated by their diminished germination. We demonstrated that optically pure citronellal enantiomers were reduced to optically pure citronellol enantiomers with retention of the configuration both in isolated wheat embryos and endosperms. Our findings reveal the potential of essential oils as allelopathic agents providing an insight into their mechanism of action and persistence. Copyright
- Cavalieri, Andrea,Fischer, Ravit,Larkov, Olga,Dudai, Nativ
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p. 419 - 426
(2014/04/03)
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- Metal-free, hydroacylation of CC and NN bonds via aerobic C-H activation of aldehydes, and reaction of the products thereof
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In this report, a thorough evaluation of the use of aerobically initiated, metal-free hydroacylation of various CC and NN acceptor molecules with a wide range of aldehydes is presented. The aerobic-activation conditions that have been developed are in sharp contrast to previous conditions for hydroacylation, which tend to use transition metals, peroxides that require thermal or photochemical degradation, or N-heterocyclic carbenes. The mildness of the conditions enables a number of reactions involving sensitive reaction partners and, perhaps most significantly, allows for α-functionalised chiral aldehydes to undergo radical-based hydroacylation with complete retention of optical purity. We also demonstrate how the resulting hydroacylation products can be transformed into other useful intermediates, such as γ-keto- sulfonamides, sultams, sultones, cyclic N-sulfonyl imines and amides.
- Chudasama, Vijay,Akhbar, Ahmed R.,Bahou, Karim A.,Fitzmaurice, Richard J.,Caddick, Stephen
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p. 7301 - 7317
(2013/10/22)
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- Traceless stereoinduction in the one-pot assembly of all three rings of hexahydrodibenzopyrans
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A one-pot method has been developed for the synthesis of all three rings of the hexahydrodibenzopyran ring system. This process involves a tandem sequence consisting of a benzannulation reaction of an alkenyl Fischer carbene complex and an alkyne followed by an elimination reaction that generates an o-quinone methide chromium tricarbonyl complex that is finally followed by an intramolecular heteroatom Diels-Alder cycloaddition. The stereoinduction for the overall process begins with the transfer of stereochemical information from the chiral center at the propargylic ether in the alkyne to the planar center of chirality in the in situ generated arene chromium tricarbonyl complexed intermediate and finally, after base-induced elimination to generate an o-quinone methide chromium tricarbonyl complexed intermediate, a transfer of chirality from the planar center of chirality in the o-quinone methide complex to the two new centers of chirality at positions 6a and 10a in the hexahydrodibenzopyran products upon intramolecular Diels-Alder reaction. The reactions of diastereomeric chiral propargyl ethers that contain an additional center of chirality can lead to high diastereoselectivity in the matched case and to low selectivity in the mismatched case. Copyright
- Korthals, Keith A.,Wulff, William D.
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p. 2898 - 2899
(2008/09/20)
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- Regio- and Stereoselective Hydrogenation of Conjugated Carbonyl Compounds via Palladium Assisted Hydrogen Transfer by Ammonium Formate
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Excellent regio- and stereoselectivity has been achieved in the hydrogenation of C=C bond conjugated to carbonyl group in presence of olefin by ammonium formate/Pd-C system.
- Ranu, Brindaban C.,Sarkar, Arunkanti
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p. 8649 - 8650
(2007/10/02)
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- OZONOLYSIS OF ALKENES AND THE REACTIONS OF POLYFUNCTIONAL COMPOUNDS LIII.SYNTHESIS OF THE ESTERS OF 2,3-DIHYDRO DERIVATIVES OF TRI-, DI-, AND MONOPRENOIC ACIDS
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The esters of the 2,3-dihydro derivatives of geranylgeranic, farnesylic, and geranic acids (di-, sesqui-, and monoterpenoid acids) were synthesized from the products from ozonolysis of 1,5,9-trimethyl-1E,5E,9E-cyclododecatriene.
- Odinokov, V. N.,Kukovinets, O. S.,Sakharova, N. I.,Tolstikov, G. A.
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- CITRONELLYL CITRONELLATE AND CITRONELLYL GERANATE IN THE EUROPEAN HORNET, Vespa crabro (HYMENOPTERA: VESPIDAE)
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Citronellyl citronellate and citronellyl geranate, new insect natural products, have been identified in the van der Vecht's gland of the European hornet.
- Wheeler, J. W.,Ayorinde, F. O.,Greene, A.,Duffield, R. M.
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p. 2071 - 2072
(2007/10/02)
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- Photoreactions of α-sulfonyloxyketones
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Earlier work on the photochemistry of α-sulfonyloxyketones uncovered their propensity to form the corresponding α-ketocarbonium ions on photolysis.Typical reactions such as intramolecular cyclizations, carbonium ion rearrangements, and solvent trapping were found.This paper describes an attempt to extend this reaction to a general synthetic technique for polyene cyclizations.During the course of this work two other major reaction pathways were found.The first is an α-keto carbonium ion to acylium ion rearrangement and the second is a photoreduction-elimination process that leads to an α-keto radical rather than the corresponding cation.
- Charlton, James Leslie.,Lai, Hoi Kiong.,Lypka, Gerald Nicholas
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p. 458 - 462
(2007/10/02)
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- A NOVEL METHOD FOR THE TERPENE SYNTHESIS BY THE RING-OPENING REACTION OF β-METHYL-β-PROPIOLACTONE
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A new route for the terpene synthesis is investigated, which undergoes via terpene carboxylic acids as key intermediates obtained by the regiospecific ring opening of β-methyl-β-propiolactone with cuprate or with a Grignard reagent in the presence of a copper catalyst.
- Fujisawa, Tamotsu,Sato, Toshio,Kawara, Tatsuo,Noda, Atsunari,Obinata,Toshiyuki
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p. 2553 - 2554
(2007/10/02)
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