1007-32-5Relevant articles and documents
Rhodium-Catalyzed Room Temperature C-C Activation of Cyclopropanol for One-Step Access to Diverse 1,6-Diketones
Ghosh, Asit,Pati, Bedadyuti Vedvyas,Ravikumar, P. C.
, (2020)
A rhodium-catalyzed room temperature C-C activation of cyclopropanol has been demonstrated for the single-step synthesis of a range of electronically and sterically distinct 1,6-diketones. This reaction proceeds efficiently in shorter reaction time following a highly atom-economical pathway. To illustrate the synthetic potential of 1,6-diketones, aldol and macrocyclization reactions have been successfully demonstrated. Preliminary mechanistic studies revealed the involvement of nonradical pathways.
A convenient catalytic oxidative 1,2-shift of arylalkenes for preparation of α-aryl ketones mediated by NaI
Zhu, Min,Zhao, Yang
, p. 248 - 250 (2015)
Using a catalytic amount of NaI and a stoichiometric oxidant Oxone@, a convenient procedure has been developed for the catalytic oxidative 1,2-shift of arylalkenes in CH3CN/H2O at room temperature, which provides the corresponding α-aryl ketones in moderate to good yields. In this protocol, sodium iodide is first oxidized into hypoiodous acid, which reacts with arylalkene to afford iodohydrin. Then, the iodohydrin is transformed into the α-aryl ketone via an oxidative 1,2-shift rearrangement.
Electrochemical synthesis of ketones from acid chlorides and alkyl and aryl halides catalysed by nickel complexes
Marzouk, H.,Rollin, Y.,Folest, J. C.,Nedelec, J. Y.,Perichon, J.
, p. C47 - C50 (1989)
The nickel-catalysed electrochemical cross-coupling of acid chlorides and alkyl or aryl halides in acetonitrile affords unsymmetric ketones in good to high yields.The reaction can be performed under very simple and mild conditions in a diaphragmless cell.A zinc rod as the sacrificial anode has been found to be the most efficient.
Rational Design of a Metallocatalytic Cavitand for Regioselective Hydration of Specific Alkynes
Endo, Naoki,Inoue, Mami,Iwasawa, Tetsuo
, p. 1136 - 1140 (2018)
The synthesis of a functionalized supramolecular cavitand with inwardly oriented AuI and P=O moieties was explored, including its catalytic proclivity in the selective hydration of internal alkynes. The cavitand works as a supramolecular flask device: AuI coordinates to the triple bond, the P=O moiety connects with a H2O molecule, and the cavity favors folding of a single alkynyl side chain. Several tests of different substrate patterns indicated that the cavity was substrate specific, similar to enzymatic catalysis.
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House et al.
, p. 4099,4104 (1960)
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Novel Electrophilic Species Equivalent to α-Keto Cations. Reactions of O,O-Diprotonated Nitro Olefins with Benzenes Yield Arylmethyl Ketones
Okabe, Kazuaki,Ohwada, Tomohiko,Ohta, Toshiharu,Shudo, Koichi
, p. 733 - 734 (1989)
The N,N-dihydroxyiminium carbenium ions formed by O,O-diprotonation of nitro olefins in a strong acid, trifluoromethanesulfonic acid (TFSA), are discrete and novel dipositively charged species.The dications formed from α-substitited nitroethylenes are reactive electrophiles to give α-arylated ketones in high yields.This constitutes a versatile synthetic method for the preparation of α-arylated ketones, which are difficult to synthesize by the conventional Friedel-Crafts reactions.
Variations on the Theme of JohnPhos Gold(I) Catalysts: Arsine and Carbene Complexes with Similar Architectures
Carreras, Javier,Pereira, Ana,Zanini, Margherita,Echavarren, Antonio M.
, p. 3588 - 3597 (2018)
Arsine and carbene gold(I) complexes with architectures closely related to those of 2-(di-tert-butylphosphino)biphenyl gold(I) complexes have been prepared and structurally characterized. As predicted, 2-(di-tert-butylarsine)biphenyl gold(I) complexes are more electrophilic catalysts in comparison to their phosphine analogues, whereas those based on 4-arylindazole behave similarly to NHC-gold(I) catalysts.
Regioselective Isomerization of 2,3-Disubstituted Epoxides to Ketones: An Alternative to the Wacker Oxidation of Internal Alkenes
Lamb, Jessica R.,Mulzer, Michael,Lapointe, Anne M.,Coates, Geoffrey W.
, p. 15049 - 15054 (2015)
We report an alternative pathway to the Wacker oxidation of internal olefins involving epoxidation of trans-alkenes followed by a mild and highly regioselective isomerization to give the major ketone isomers in 66-98% yield. Preliminary kinetics and isotope labeling studies suggest epoxide ring opening as the turnover limiting step in our proposed mechanism. A similar catalytic system was applied to the kinetic resolution of select trans-epoxides to give synthetically useful selectivity factors of 17-23 for benzyl-substituted substrates.
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Shono,T. et al.
, p. 2667 - 2670 (1977)
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Facile Fragmentations of Alkeny1(aryl)iodonium Triflates
Hinkle, Robert J.,Thomas, David B.
, p. 7534 - 7535 (1997)
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Silver- and Acid-Free Catalysis by Polyoxometalate-Assisted Phosphanegold(I) Species for Hydration of Diphenylacetylene
Arai, Hidekazu,Yoshida, Takuya,Nagashima, Eri,Hatayama, Akifumi,Horie, Shogo,Matsunaga, Satoshi,Nomiya, Kenji
, p. 1658 - 1666 (2016)
A DMSO-soluble intercluster compound consisting of a tetra{phosphanegold(I)}oxonium cation and an α-Keggin polyoxometalate (POM) anion, [{Au(PPh3)}4(μ4-O)]3[α-PW12O40]2 (1), was found to be an effective precatalyst for the silver- and acid-free catalysis of diphenylacetylene hydration (0.67 mol % catalyst; conversions 36.1%, 55.2%, and 93.7% after 4, 6, and 24 h reactions, respectively). The reaction proceeded in the suspended system in 6 mL of 1,4-dioxane/water (4:1) at 80 °C because of the low solubility of 1. Similar POM-based phosphanegold(I) compounds [{{Au(PPh3)}4(μ4-O)}{{Au(PPh3)}3(μ3-O)}][α-PW12O40]·EtOH (5), which is composed of a heptakis{triphenylphosphanegold(I)}dioxonium cation and an α-Keggin POM anion, and [Au(CH3CN)(PPh3)]3[α-PMo12O40] (6), which consists of an acid-free monomeric phosphanegold(I) acetonitrile cation and an α-Keggin molybdo-POM anion, also exhibited acid-free catalysis for the hydration of diphenylacetylene. An induction period was observed in the catalysis by 5. On the other hand, their component species, or phosphanegold(I) species without the POM anion, such as [{Au(PPh3)}4(μ4-O)](BF4)2 (2) and [{Au(PPh3)}3(μ3-O)]BF4 (3), and the monomeric phosphanegold(I) complex [Au(RS-pyrrld)(PPh3)] (4) (RS-Hpyrrld = RS-2-pyrrolidone-5-carboxylic acid), the last of which has been used as a precursor for the preparation of 1, 5, and 6, showed poor activities in this reaction (0.67 mol % catalysts; conversions 1.8%, 1.7%, and 0.5% after 24 h reactions, respectively). However, upon adding the free-acid form of Keggin POM, i.e., H3[α-PW12O40]·7H2O (H-POM: 0.67 mol %), 2-4 exhibited remarkably enhanced activities (conversion 97.6% each after 24 h reactions). In contrast, the activities were not enhanced after adding either the sodium salt of the Keggin POM, Na3[α-PW12O40]·8H2O (Na-POM; 0.67 mol %), or a Br?nsted acid 10% HBF4 aqueous solution (0.67 mol %). Both H-POM and Na-POM themselves exhibited no activity. Catalysis by the phosphanegold(I) species for diphenylacetylene hydration was influenced significantly under the free-acid form or sodium salt of the Keggin POM. Acid-free catalytic hydration by 1 of other alkynes, such as phenylacetylene and 1-phenyl-1-butyne, was also examined.
Radical-Based C?C Bond-Forming Processes Enabled by the Photoexcitation of 4-Alkyl-1,4-dihydropyridines
Buzzetti, Luca,Prieto, Alexis,Roy, Sudipta Raha,Melchiorre, Paolo
, p. 15039 - 15043 (2017)
We report herein that 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) can directly reach an electronically excited state upon light absorption and trigger the generation of C(sp3)-centered radicals without the need for an external photocatalyst. Selective excitation with a violet-light-emitting diode turns alkyl-DHPs into strong reducing agents that can activate reagents through single-electron transfer manifolds while undergoing homolytic cleavage to generate radicals. We used this photochemical dual-reactivity profile to trigger radical-based carbon–carbon bond-forming processes, including nickel-catalyzed cross-coupling reactions.
Ruthenium-catalyzed redox isomerization/transfer hydrogenation in organic and aqueous media: A one-pot tandem process for the reduction of allylic alcohols
Cadierno, Victorio,Crochet, Pascale,Francos, Javier,Garcia-Garrido, Sergio E.,Gimeno, Jose,Nebra, Noel
, p. 1992 - 2000 (2009)
The hexamethylbenzene-ruthenium(ii) dimer [{RuCl(μ-Cl) (η6-C6Me6)}2] 1 and the mononuclear bis(allyl)-ruthenium(iv) complex [RuCl2(η 3:η2:η3-C12H 18)]2, associated with base and a hydrogen donor, were found to be active catalysts for the selective reduction of the CC bond of allylic alcohols both in organic and aqueous media. The process, which proceeds in a one-pot manner, involves a sequence of two independent reactions: (i) the initial redox-isomerization of the allylic alcohol, and (ii) subsequent transfer hydrogenation of the resulting carbonyl compound. The highly efficient transformation reported herein represents, not only an illustrative example of auto-tandem catalysis, but also an appealing alternative to the classical transition-metal catalyzed CC hydrogenations of allylic alcohols. The process has been successfully applied to aromatic as well as aliphatic substrates affording the corresponding saturated alcohols in 45-100% yields after 1.5-24 h. The best performances were reached using (i) 1-5 mol% of 1 or 2, 2-10 mol% of Cs2CO3, and propan-2-ol or (ii) 1-5 mol% of 1 or 2, 10-15 equivalents of NaO2CH, and water. The catalytic efficiency is strongly related to the structure of the allylic alcohol employed. Thus, in propan-2-ol, the reaction rate essentially depends on the steric requirement around the CC bond, therefore decreasing with the increasing number of substituents. On other hand, in water the transformation is favoured for primary allylic alcohols vs. secondary ones.
PALLADIUM-CATALYZED CARBONYLATIVE CROSS-COUPLING OF ORGANOBORANES WITH ARYL IODIDES OR BENZYL HALIDES IN THE PRESENCE OF BIS(ACETYLACETONATO)ZINC (II)
Wakita, Yoshiaki,Yasunaga, Tomoyuki,Akita, Masahiro,Kojima, Masaharu
, p. C17 - C20 (1986)
Carbonylative cross-coupling reactions of organoboranes with aryl iodides and benzyl halides successfully catalyzed by dichlorobis(triphenylphosphine)palladium(II) in the presence of bis(acetylacetonato)zinc(II) procedure unsymmetrical ketones in reasonable yields.
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Sekine,M. et al.
, p. 4475 - 4478 (1979)
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Matched Coupling of Propargylic Carbonates with Cyclopropanols
Wu, Penglin,Jia, Minqiang,Lin, Weilong,Ma, Shengming
, p. 554 - 557 (2018)
The ring opening-coupling reaction of cyclopropanols with propargylic carbonates affording synthetically attractive allenyl ketones has been developed. The mechanism involves the ligand-exchange reaction of in situ formed allenyl palladium methoxide with cyclopropanols followed by carbon-carbon bond cleavage and reductive elimination. The reactions proceeded smoothly under mild reaction conditions with Pd(0)/XPhos catalysis in the absence of any external base and displayed a wide scope and application to a steroidal skeleton. The efficiency of chirality transfer and synthetic utility of the allene products have also been demonstrated.
A Pd-catalyzed ring opening coupling reaction of 2,3-allenylic carbonates with cyclopropanols
Lin, Jie,Zhu, Tonghao,Jia, Minqiang,Ma, Shengming
, p. 4523 - 4526 (2019)
A palladium-catalyzed coupling reaction of 2,3-allenylic carbonates with cyclopropanols was developed, affording valuable 1,3-diene products with different functional groups efficiently under mild reaction conditions. Gram scale synthesis was easily conducted with synthetic transformations demonstrated.
Trichloroisocyanuric acid, as an industrial chemical, promotes transthioacetalization of diacetals of 2,2-bis (hydroxymethyl)-1,3-propanediol and cleavage of thioacetals
Firouzabadi, Habib,Iranpoor, Nasser,Hazarkhani, Hassan
, p. 2571 - 2577 (2002)
Trichloroisocyanuric acid has been used as a mild, efficient, and new catalyst for transthioacetalization of diacetals of 2,2-bis (hydroxymethyl)-1,3-propanediol in CH2Cl2 at room temperature. A clean, easy, and general method for efficient deprotection of thioacetals to their corresponding carbonyl compounds using trichloroisocyanuric acid/silica gel and water system also is described.
A novel application of chloroperoxidase: Preparation of gem-halonitro compounds
Zaks, Aleksey,Yabannavar, Asha V.,Dodds, David R.,Evans, C. Anderson,Das, Pradip R.,Malchow, Rodney
, p. 8692 - 8695 (1996)
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Asinger et al.
, p. 631 (1967)
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Asymmetric Catalytic Epoxidation of Terminal Enones for the Synthesis of Triazole Antifungal Agents
Feng, Xiaoming,He, Qianwen,Liu, Xiaohua,Zhang, Dong,Zhang, Fengcai
supporting information, p. 6961 - 6966 (2021/09/11)
An enantioselective epoxidation of α-substituted vinyl ketones was realized to construct the key epoxide intermediates for the synthesis of various triazole antifungal agents. The reaction proceeded efficiently in high yields with good enantioselectivities by employing a chiral N,N′-dioxide/ScIII complex as the chiral catalyst and 35% aq. H2O2 as the oxidant. It enabled the facile transformation for optically active isavuconazole, efinaconazole, and other potential antifungal agents.
Ketone Synthesis from Benzyldiboronates and Esters: Leveraging α-Boryl Carbanions for Carbon-Carbon Bond Formation
Lee, Boran,Chirik, Paul J.
supporting information, p. 2429 - 2437 (2020/03/03)
An alkoxide-promoted method for the synthesis of ketones from readily available esters and benzyldiboronates is described. The synthetic method is compatible with a host of sterically differentiated alkyl groups, alkenes, acidic protons α to carbonyl groups, tertiary amides, and aryl rings having common organic functional groups. With esters bearing α-stereocenters, high enantiomeric excess was maintained during ketone formation, establishing minimal competing racemization by deprotonation. Monitoring the reaction between benzyldiboronate and LiOtBu in THF at 23 °C allowed for the identification of products arising from deborylation to form an α-boryl carbanion, deprotonation, and alkoxide addition to form an "-ate" complex. Addition of 4-trifluoromethylbenzoate to this mixture established the α-boryl carbanion as the intermediate responsible for C-C bond formation and ultimately ketone synthesis. Elucidation of the role of this intermediate leveraged additional bond-forming chemistry and enabled the one-pot synthesis of ketones with α-halogen atoms and quaternary centers with four-different carbon substituents.
