- Hydroxide-promoted Reduction of the Corrole Complexes of Cobalt(III) and Iron(III) in the Presence of Olefin
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An oxygenation system effective for electronrich olefins which involves the hydroxide ion, provides electrons required for reduction of the corrole complexes of cobalt(III) and iron(III).
- Murakami, Yukito,Aoyama, Yasuhiro,Hayashida, Mikio
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- Photochemical polar addition of 1,1-diphenylethene using photosensitive surfactant in stable oil-in-water emulsion
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An aq NaOH solution of the photosensitive surfactant 1 was mixed with 1,1-diphenylethene 2 to form a stable oil-in-water emulsion and excitation of the emulsion afforded the alcohol 3 in good yield without stirring. The photosensitive surfactant 1 works more efficiently in heterogeneous system (in water) than in homogeneous system (in organic solvent).
- Yoshimi, Yasuharu,Higuchi, Michiya,Itou, Tatsuya,Hatanaka, Minoru
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- Cleavage of Si-Ar bond vs Si-Me bond: A remarkable counterion effect on reactivity
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Formation of distinctly different products from the same alkoxide intermediate indicates a strong dependence of reaction pathways on counterions.
- Tipparaju, Suresh Kumar,Mandal, Sunil K.,Sur, Surojit,Puranik, Vedavati G.,Sarkar, Amitabha
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- PREPARATION AND REACTIONS OF SOLVENT-FREE ARYLCALCIUM HALIDES, ArCaX (X = F, Cl, Br)
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Reactions of aryl halide vapor and calcium metal vapor were found to give the corresponding arylcalcium halides, ArCaX (X = F, Cl, and Br).Phenylcalcium halide, PhCaX (X = F and Cl), reacted with trimethylchlorosilane to give phenyltrimethylsilane.The reactions of phenylcalcium halides with acetone and benzaldehyde readily gave good yields of 1-methyl-1-phenylethanol and diphenylmethanol, respectively.Phenylcalcium halides reacted slowly with acetonitrile to afford acetophenone in poor yields.With ethyl acetate, phenylcalcium halides gave a mixture of 1,1-diphenylethanol and acetophenone.
- Mochida, K.,Ogawa, H.
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- Kinetic Isotope Effect and Substituent Effect Study on the Grignard Reaction of MeMgI with Benzophenone. A Rate-Determining C-C Bond Formation
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The carbonyl carbon-14 kinetic isotope effect and substituent effects were determined for the reaction of MeMgI with benzophenone.The observed large carbon isotope effect (14k/12k=1.056) together with the large steric effect on reactivity introduced by o-substituents on benzophenone indicated that the C-C bond formation is the rate-determinig step of the Grignard reaction.
- Yamataka, Hiroshi,Matsuyama, Toyoki,Hanafusa, Terukiyo
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Read Online
- To Rebound or...Rebound? Evidence for the "alternative Rebound" mechanism in Ca'H Oxidations by the systems nonheme Mn Complex/H2O2/carboxylic acid
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In this work, it has been shown that aliphatic Ca'H oxidations by bioinspired catalyst systems Mn aminopyridine complex/H2O2/carboxylic acid in acetonitrile afford predominantly a mixture of the corresponding alcohol and the ester. The alcohol/ester ratio is higher for catalysts bearing electron-donating groups at the aminopyridine core. Isotopic labeling studies witness that the oxygen atom of the alcohol originates from the H2O2molecule, while the ester oxygen comes exclusively from the acid. Oxidation of ethylbenzene in the presence of acetic acid affords enantiomerically enriched 1-phenylethanol and 1-phenyl acetate, with close enantioselectivities and the same sign of absolute chirality. Experimental data and density functional theory calculations provide evidence in favor of the rate-limiting benzylic H atom abstraction by the high-spin (S = 1) [LMnV(O)OAc]2+active species followed by competitive OH/OC(O)R rebound. This mechanism has been unprecedented for Ca'H oxidations catalyzed by bioinspired Mn complexes. The trends governing the alcohol/ester ratios have been rationalized in terms of steric properties of the catalyst, acid, and substrate. copy; 2021 American Chemical Society.
- Ottenbacher, Roman V.,Bryliakova, Anna A.,Shashkov, Mikhail V.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
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p. 5517 - 5524
(2021/05/31)
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- Direct Nucleophilic Substitution of Alcohols Using an Immobilized Oxovanadium Catalyst
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Direct nucleophilic substitution of alcohols with thiols or carbon nucleophiles was achieved using a mesoporous silica-supported oxovanadium catalyst (VMPS4). Benzyl and allyl alcohols were compatible in this reaction under mild conditions, affording the products in high yields. The VMPS4 catalyst showed excellent chemoselectivity toward alcohols in the presence of acid-labile functional groups, which is in contrast to that observed for the commonly used Lewis acid catalysts, which exhibit poor selectivity. The VMPS4 catalyst could be recycled by simple centrifugation, and the catalytic activity was maintained over seven cycles.
- Nishio, Tomoya,Yoshioka, Shin,Hasegawa, Kai,Yahata, Kenzo,Kanomata, Kyohei,Akai, Shuji
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supporting information
p. 4417 - 4422
(2021/07/16)
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- A one-pot two-step synthesis of tertiary alcohols combining the biocatalytic laccase/TEMPO oxidation system with organolithium reagents in aerobic aqueous media at room temperature
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The one-pot/two-step combination of enzymes and polar organometallic chemistry in aqueous media is for the first time presented as a proof-of-concept study. The unprecedented combination of the catalytic oxidation of secondary alcohols by the system laccase/TEMPO with the ultrafast addition (3 s reaction time) of polar organometallic reagents (RLi/RMgX) to thein situformed ketones, run under air at room temperature, allows the straightforward and chemoselective synthesis of tertiary alcohols with broad substrate scope and excellent conversions (up to 96%).
- Capriati, Vito,Cicco, Luciana,García-álvarez, Joaquín,González-Sabín, Javier,Lecuna, Ramón,Presa Soto, Alejandro,Ríos-Lombardía, Nicolás,Ramos-Martín, Marina,Vitale, Paola
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p. 13534 - 13537
(2021/12/23)
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- Shuttle arylation by Rh(I) catalyzed reversible carbon–carbon bond activation of unstrained alcohols
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The advent of transfer hydrogenation and borrowing hydrogen reactions paved the way to manipulate simple alcohols in previously unthinkable manners and circumvented the need for hydrogen gas. Analogously, transfer hydrocarbylation could greatly increase the versatility of tertiary alcohols. However, this reaction remains unexplored because of the challenges associated with the catalytic cleavage of unactivated C–C bonds. Herein, we report a rhodium(I)-catalyzed shuttle arylation cleaving the C(sp2)–C(sp3) bond in unstrained triaryl alcohols via a redox-neutral β-carbon elimination mechanism. A selective transfer hydrocarbylation of substituted (hetero)aryl groups from tertiary alcohols to ketones was realized, employing benign alcohols as latent C-nucleophiles. All preliminary mechanistic experiments support a reversible β-carbon elimination/migratory insertion mechanism. In a broader context, this novel reactivity offers a new platform for the manipulation of tertiary alcohols in catalysis.
- Lutz, Marius D.R.,Gasser, Valentina C.M.,Morandi, Bill
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supporting information
p. 1108 - 1119
(2021/04/19)
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- Expeditious and practical synthesis of tertiary alcohols from esters enabled by highly polarized organometallic compounds under aerobic conditions in Deep Eutectic Solvents or bulk water
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An efficient protocol was developed for the synthesis of tertiary alcohols via nucleophilic addition of organometallic compounds of s-block elements (Grignard and organolithium reagents) to esters performed in the biodegradable choline chloride/urea eutectic mixture or in water. This approach displays a broad substrate scope, with the addition reaction proceeding quickly (20 s reaction time) and cleanly, at ambient temperature and under air, straightforwardly furnishing the expected tertiary alcohols in yields of up to 98%. The practicability of the method is exemplified by the sustainable synthesis of some representative S-trityl-L-cysteine derivatives, which are a potent class of Eg5 inhibitors, also via telescoped one-pot processes.
- Quivelli, Andrea F.,D'Addato, Giovanna,Vitale, Paola,García-álvarez, Joaquín,Perna, Filippo M.,Capriati, Vito
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- Composition containing diclofenapyr and pretilachlor
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The invention discloses a composition containing diclofenapyr and pretilachlor, which is prepared by wrapping a core material with microencapsulated liquid. When the composition is used, the weed in the paddy field absorbs chitosan, and the chitosan can increase the absorption rate of the weed to the diclofenapyr and the pretilachlor, and the intermediate 9 on the chitosan surface is absorbed by the weed and the rice. , The damage to the rice caused by the diclofenapyr and the pretilachlor is greatly reduced, so that the composition does not affect the rice while killing weeds.
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Paragraph 0015; 0039; 0044-0045; 0053; 0058-0059; 0067; ...
(2021/11/21)
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- Isopropanol as a hydrogen source for single atom cobalt-catalyzed Wacker-type oxidation
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The first example of a heterogeneous cobalt catalytic system for Wacker-type oxidation catalyzed by a single atom dispersed Co-N/C catalyst using alcohol as the hydrogen source under an oxygen atmosphere is presented. By combining a well-designed, controlled experiment and various methods of characterization, we determined that single atom cobalt was the active center rather than nanoparticle or oxide counterparts.
- An, Yue,Chen, Bo,Gao, Shuang,Huang, Guanwang,Luo, Huihui,Shang, Sensen,Wang, Lianyue
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p. 2769 - 2773
(2020/06/17)
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- Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
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A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
- Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
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supporting information
p. 14286 - 14294
(2020/09/15)
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- Iron-catalysed 1,2-aryl migration of tertiary azides
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1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
- Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
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supporting information
p. 11685 - 11688
(2020/10/19)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Base-promoted addition of DMA with 1,1-diarylethylenes: Application to a total synthesis of (-)-sacidumlignan B
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A base-promoted addition of DMA (N,N-dimethylacetamide) to 1,1-diarylethylenes has been developed, and it provides a new strategy for the synthesis of N,N-dimethyl-4,4-diarylbutanamides from 1,1-diarylethylenes at room temperature. This method allows us to achieve the goal of synthesizing (-)-sacidumlignan B, and provides simple operation and broad substrate scope by avoiding the use of transition metal catalysts.
- Luo, Zhen-Biao,Peng, Yu,Wang, Ya-Wen
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supporting information
p. 2054 - 2057
(2020/03/27)
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- A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
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A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
- Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
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p. 5019 - 5026
(2020/05/01)
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- Oxygenation of styrenes catalyzed by N-doped carbon incarcerated cobalt nanoparticles
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NCI-Co catalyzed olefin oxygenation reactions were investigated. Among the metals examined, including noble metals, the reaction proceeded specifically on Co catalysts, and nitrogen dopant was crucial for the catalytic activity. The presence of NaBH4 as a hydride source, the corresponding alcohols were obtained in high yields. The substrates bearing a reductant-sensitive functional group were made tolerant by changing the reductant and using an additive, and furthermore, the corresponding ketones were accessed by changing reaction conditions. A preliminary examination of other SOMOphiles suggested that the heterogeneous catalyst systems have the potential to be applied to more general hydrofunctionalization of olefins to form various kinds of bonds. Several mechanistic studies suggested that the reaction proceeded in a heterogeneous manner and formed a radical intermediate on cobalt nanoparticle species.
- Yasukawa, Tomohiro,Kobayashi, Shū
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supporting information
p. 1980 - 1985
(2019/12/24)
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- Mn(III)-based oxidative radical ring-expansion reaction using squarate derivatives: Selective synthesis of bis(butenolide)s and the acetate monomers
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The Mn(III)-based oxidation of phenyl- and alkyl-substituted hydroxycyclobutenones selectively produced the bis(butenolide)s or the acetate monomers via the 5-endo radical cyclization depending upon the concentration of the reaction. A similar reaction of hydroxycyclobutenones bearing an alkenyl and alkynyl substituent did not produce any bis(butenolide)s or acetate monomers, but the 5-exo and 6-endo radical cyclization products including the unsaturated group. The oxidation of the hydroxycyclobutenones having an unsaturated substituent in the presence of alkenes afforded radical coupling products during the 5-exo radical cyclization. The reaction details, structure determination of the products, and the mechanism for the formation of the products are described.
- Sasaki, Jun-Ichi,Kobayashi, Makoto,Ibe, Y?suke,Nishino, Hiroshi
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p. 958 - 988
(2019/08/01)
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- Introducing Glycerol as a Sustainable Solvent to Organolithium Chemistry: Ultrafast Chemoselective Addition of Aryllithium Reagents to Nitriles under Air and at Ambient Temperature
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Edging closer towards developing air and moisture compatible polar organometallic chemistry, the chemoselective and ultrafast addition of a range of aryllithium reagents to nitriles has been accomplished by using glycerol as a solvent, at ambient temperature in the presence of air, establishing a novel sustainable access to aromatic ketones. Addition reactions occur heterogeneously (“on glycerol conditions”), where the lack of solubility of the nitriles in glycerol and the ability of the latter to form strong intermolecular hydrogen bonds seem key to favouring nucleophilic addition over competitive hydrolysis. Remarkably, PhLi exhibits a greater resistance to hydrolysis working “on glycerol” conditions than “on water”. Introducing glycerol as a new solvent in organolithium chemistry unlocks a myriad of opportunities for developing more sustainable, air and moisture tolerant main-group-metal-mediated organic synthesis.
- Rodríguez-álvarez, María J.,García-álvarez, Joaquín,Uzelac, Marina,Fairley, Michael,O'Hara, Charles T.,Hevia, Eva
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p. 1720 - 1725
(2018/01/27)
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- Catalytic Lactonization of Unactivated Aryl C-H Bonds with CO2: Experimental and Computational Investigation
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The first catalytic lactonization of unactivated aryl C-H bonds with CO2 to afford important phthalides is reported. Notably, this method features high selectivity, excellent functional group tolerance, smooth scalability, and facile product diversification. DFT calculations reveal that a novel insertion of two CO2 into the O-Pd bond of a palladacycle might be the key step, providing great potential and a different perspective for carbonylation with CO2.
- Song, Lei,Zhu, Lei,Zhang, Zhen,Ye, Jian-Heng,Yan, Si-Shun,Han, Jie-Lian,Yin, Zhu-Bao,Lan, Yu,Yu, Da-Gang
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supporting information
p. 3776 - 3779
(2018/07/21)
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- Facile synthesis of indolelactones using Mn(III)-based oxidative substitution-cyclization reaction
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Based on the oxidation of indole with Mn(OAc)3 in the presence of 1,1-diarylethenes affording 3-vinyl-substituted indoles, a similar oxidation using indole-2-carboxylic acids was evaluated in order to effectively introduce the substituent group to the C-3 position of the indolecarboxylic acids. The coupling reaction followed by oxidative cyclization smoothly proceeded at room temperature in an AcOH-HCO2H mixed solvent to give the desired indolelactones in high yields. The reaction details, the structure determination of the products and a brief reaction mechanism are described.
- Inoue, Takeshi,Nishino, Hiroshi
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p. 431 - 450
(2019/07/31)
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- Catalytic Enantioselective Arylation and Heteroarylation of Ketones with Organotitanium Reagents Generated In Situ
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A practical and useful, catalytic enantioselective method has been developed for the synthesis of tertiary diaryl and aryl heteroaryl carbinols starting from commercially available aromatic ketones and aryl or heteroaryl bromides. In this method, organotitanium reagents are generated in situ from the bromides by lithiation with nBuLi followed by transmetallation of the resulting organolithiums with ClTi(OiPr)3. Treatment of the ketones with the titanium reagents in the presence of (R)-3-(3,5-bistrifluoromehthylphenyl)-1,1′-bi-2-naphthol (BTFP-BINOL) affords the corresponding tertiary alcohols in high enantioselectivities and yields. The reaction can also start with furan and 2-thienyllithium. The method is operationally simple and can be conducted on a 10-mmol scale without any difficulties.
- Matsuda, Atsushi,Ushimaru, Tomoya,Kobayashi, Yusuke,Harada, Toshiro
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supporting information
p. 8605 - 8609
(2017/06/30)
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- Scandium(III) Trifluoromethanesulfonate Catalyzed Selective Reactions of Donor–Acceptor Cyclopropanes with 1,1-Diphenylethanols: An Approach to Polysubstituted Olefins
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An unexpected synthetic approach to polysubstituted olefins through the scandium(III) trifluoromethanesulfonate catalyzed ring-opening reaction of donor–acceptor cyclopropanes with 1,1-diphenylethanols was developed. The reactions, which are experimentally easy to handle, feature tolerance of various functional groups and mild reaction conditions. On the basis of experimental evidence, a plausible mechanism was also proposed.
- Zhu, Xiaoyan,Hong, Gang,Hu, Chen,Wu, Shengying,Wang, Limin
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supporting information
p. 1547 - 1551
(2017/04/01)
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- Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
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Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
- Lei, Chuanhu,Yip, Yong Jie,Zhou, Jianrong Steve
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supporting information
p. 6086 - 6089
(2017/05/08)
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- Aluminum complexes containing salicylbenzoxazole ligands and their application in the ring-opening polymerization of: Rac -lactide and ?-caprolactone
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Two series of four-coordinate aluminum (1a-9a) and five-coordinate aluminum (1b-9b) complexes were successfully synthesized via the reactions between the corresponding salicylbenzoxazole ligands and 1 or 0.5 equivalents of AlMe3, respectively. The synthesized aluminum complexes were characterized by 1H and 13C NMR spectroscopy and elemental analysis. The solid-state structures of complexes 7a and 1b were determined using single crystal X-ray diffraction. Upon addition of 1 equivalent of benzyl alcohol, all complexes were efficient initiators for the ring-opening polymerization (ROP) of rac-lactide (rac-LA) and ?-caprolactone (?-CL). The polymerizations were living with a good control over molecular weights and molecular weight distributions. Under immortal polymerization conditions, all four-coordinate aluminum complexes (1b-9b) exhibited a living polymerization with the obtained molecular weights proportional to the ratio of monomer/benzyl alcohol and the PDIs were narrow. Kinetic studies revealed that both rac-LA and ?-CL polymerizations mediated by all complexes were first-order in monomers. The effects of ligand structure and coordination geometry on the catalytic activity and stereoselectivity were discussed. A good isoselectivity control was achieved for the polymerizations mediated by complexes 4b (Pm = 0.75), 5b (Pm = 0.74), and 9b (Pm = 0.74).
- Sumrit, Pattarawut,Chuawong, Pitak,Nanok, Tanin,Duangthongyou, Tanwawan,Hormnirun, Pimpa
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supporting information
p. 9250 - 9266
(2016/06/14)
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- The Barbier-Grignard-Type Arylation of Ketones and Unexpected Cross-Coupling of Phenolic Ketones using Unactivated Aryl Bromides
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A novel, highly versatile and efficient method has been developed for the Barbier-Grignard-type arylation of ketones and an unexpected cross-coupling of phenolic ketones was observed using unactivated bromides and magnesium in tetrahydrofuran/toluene at 96°C promoted by multicatalysts of cupric bromide (15 mol%), bismuth chloride (5 mol%) and silver bromide (10 mol%). The substituent and electronic effects on the reaction have been discussed. High yields of arylation and cross-coupling have been attained under mild conditions. A novel reasonable mechanism involving a quinone intermediate is proposed. The high chemical selectivity in the cross-coupling to the hydroxy group of phenolic ketones should help ketones find new applications.
- Wen, Yunming,Chen, Guifang,Huang, Shiqiang,Tang, Yu,Yang, Jun,Zhang, Yuanming
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p. 947 - 957
(2016/04/05)
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- Al(OTf)3: An efficient lewis acid additive for domino addition-elimination of Grignard reagents to activated ketones
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It has been demonstrated that aluminium triflate in either stoichiometric or catalytic quantities facilitates the addition-elimination of Grignard reagents to electron-rich ketones, such as methoxy substituted acetophenones, propiophenone and chromanone in a one-pot process, and that it has an enhancing effect on the addition of these reagents to the ketones. It has also been found that the reactions are highly stereoselective towards one regioisomer of the alkene in the case of oxygenated aryl-alkyl substituted substrates, but not when the elimination originates from a double benzylic alcohol intermediate.
- Pieterse, Tanya,Visser, Melanie,Marais, Charlene,Bezuidenhoudt, Barend C. B.
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supporting information
p. 1541 - 1546
(2016/06/14)
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- A 1,1-diphenyl ethylene preparation method
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The invention discloses a preparation method of 1,1-diphenylethylene shown in a formula (V). The method comprises the steps of firstly carrying out reaction on bromobenzene and magnesium chips in anhydrous 2-methyltetrahydrofuran to obtain a phenylmagnesium bromide Grignard reagent, and then dripping acetophenone into the phenylmagnesium bromide Grignard reagent to react, so as to generate 1,1-diphenylethanol; finally, dewatering 1,1-diphenylethanol in the presence of a sulfoacid functional ionic liquid catalyst, so as to obtain 1,1-diphenylethylene shown in the formula (V). The preparation method disclosed by the invention is short in reaction step, mild in condition, simple and convenient to operate, high in product yield, low in production cost, friendly to environment, and applicable to industrial production.
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Paragraph 0044; 0045
(2016/10/09)
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- Photoredox removal of p-methoxybenzyl ether protecting group with hydrogen peroxide as terminal oxidant
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We report a mild protocol for removal of the p-methoxybenzyl ether protecting group under acidic conditions with eosin Y combined with LEDs as a photoredox catalysis system and hydrogen peroxide as the terminal oxidant. This protocol is compatible with ethers derived from primary, secondary, and tertiary alcohols, as well as with various functional groups. The protocol showed unusual selectivity for a tertiary ether over a primary ether. The scale up to gram scale is also explored and identical reactivity is observed.
- Liu, Zheng,Zhang, Yi,Cai, Zheren,Sun, Hao,Cheng, Xu
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supporting information
p. 589 - 593
(2015/03/05)
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- Advanced Synthesis of Dihydrofurans: Effect of Formic Acid on the Mn(III)-Based Oxidation
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The Mn(III)-based oxidation of a tertiary alkylamine, such as nitrilotris(ethane-2,1-diyl) tris(3-oxobutanoate) (1) with 1,1-diphenylethene (2a), effectively proceeded in an acetic acid-formic acid mixed solvent to give nitrilotris(ethane-2,1-diyl) tris(2-methyl-5,5-diphenyl-4,5-dihydrofuran-3-carboxylate) (3). Other typical Mn(III)-based reactions of various β-diketo esters 4a-e, 2,4-pentanedione (6a), malonic acid (6b), and diethyl malonate (6c) with 1,1-diarylthenes 2a-d were also investigated in a similar acetic acid-formic acid mixed solvent and the reaction rate was accelerated and the product yield increased.
- Matsumoto, Risa,Nishino, Hiroshi
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supporting information
p. 1807 - 1816
(2015/08/06)
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- Rhodium(I)-n-heterocyclic carbene-catalyzed addition of sodium tetraphenylborate to ketones to form tertiary alcohols
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Rhodium complexes ([Rh(COD)(NHC)Cl]) were synthesized by the reaction of bis(1,3-dialkylperhydrobenzimidazolin-2-ylidene) with [RhClCOD]2 in toluene and characterized by elemental analysis, 1H NMR, 13C NMR and IR spectroscopy. These complexes were used as catalysts for the addition of sodium tetraphenylborate to aromatic ketones and corresponding tertiary alcohols were obtained in good yields.
- Yiit, Beyhan,Yiit, Murat,?zdemir, Ismail
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p. 2562 - 2571
(2015/01/09)
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- LITHIUM-POROUS METAL OXIDE COMPOSITIONS AND LITHIUM REAGENT-POROUS METAL COMPOSITIONS
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The invention relates to lithium reagent-porous metal oxide compositions having RLi absorbed into a porous oxide. In formula RLi, R is an alkyl group, an alkenyl group, an alkyny group, an aryl group, an alkaryl group, or an NR1R2 group; R1 is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkaryl group; and R2 is hydrogen, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and an alkaryl group. The preparation and use of lithium reagent-porous metal oxide compositions having RLi absorbed into a porous oxide compositions are also described.
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Page/Page column 0065; 0066
(2014/10/29)
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- A simple and efficient copper oxide-catalyzed Barbier-Grignard reaction of unactivated aryl or alkyl bromides with ester
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An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier-Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65 C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving group of R2O-group is discussed.
- Gao, Fei,Deng, Xiang-Jun,Tang, Yu,Tang, Jin-Peng,Yang, Jun,Zhang, Yuan-Ming
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supporting information
p. 880 - 883
(2014/02/14)
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- A simple and efficient copper oxide-catalyzed Barbier-Grignard reaction of unactivated aryl or alkyl bromides with ester
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An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier-Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65 °C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving group of R2O-group is discussed.
- Gao, Fei,Deng, Xiang-Jun,Tang, Yu,Tang, Jin-Peng,Yang, Jun,Zhang, Yuan-Ming
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supporting information
p. 880 - 883
(2015/03/03)
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- Oxidizing properties of the tert-butyl hydroperoxide-tetra-tert- butoxychromium system
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tert-Butyl hydroperoxide reacts with the tetra-tert-butoxychromium by oxidizing the latter to chromyl CrV=O (C6H6, 20 C). At t-BuOOH-Cr(OBu-t)4 ratio of 2: 1 or higher, oxygen is released. The occuring processes include the formation of chromium-containing peroxides and peroxytrioxydes. The t-BuOOH-Cr(OBu-t)4 system oxidizes aromatic hydrocarbons of various structures (anthracene, 9,10-dimethylanthracene, 1,1-diphenylethylene, alkylarenes), as well as primary and secondary alcohols. Depending on the structure of the substrate, the oxidants are: in situ generated oxygen including that in the singlet state, peroxy radicals, or chromium-containing peroxides.
- Stepovik,Potkina,Poddelskii
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p. 2005 - 2017
(2014/01/17)
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- Sequential one-pot addition of excess aryl-grignard reagents and electrophiles to O-alkyl thioformates
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The sequential addition of aromatic Grignard reagents to O-alkyl thioformates proceeded to completion within 30s to give aryl benzylic sulfanes in good yields. This reaction may begin with the nucleophilic attack of the Grignard reagent onto the carbon atom of the O-alkyl thioformates, followed by the elimination of ROMgBr to generate aromatic thioaldehydes, which then react with a second molecule of the Grignard reagent at the sulfur atom to form arylsulfanyl benzylic Grignard reagents. To confirm the generation of aromatic thioaldehydes, the reaction between O-alkyl thioformates and phenyl Grignard reagent was carried out in the presence of cyclopentadiene. As a result, hetero-Diels-Alder adducts of the thioaldehyde and the diene were formed. The treatment of a mixture of the thioformate and phenyl Grignard reagent with iodine gave 1,2-bis(phenylsulfanyl)-1,2-diphenyl ethane as a product, which indicated the formation of arylsulfanyl benzylic Grignard reagents in the reaction mixture. When electrophiles were added to the Grignard reagents that were generated insitu, four-component coupling products, that is, O-alkyl thioformates, two molecules of Grignard reagents, and electrophiles, were obtained in moderate-to-good yields. The use of silyl chloride or allylic bromides gave the adducts within 5min, whereas the reaction with benzylic halides required more than 30min. The addition to carbonyl compounds was complete within 1min and the use of lithium bromide as an additive enhanced the yields of the four-component coupling products. Finally, oxiranes and imines also participated in the coupling reaction. Into the melting pot: The addition of excess aryl Grignard reagents and electrophiles to O-alkyl thioformates gives aryl sulfanes through four-component coupling reactions (see scheme). These reactions may involve the formation of aromatic thioaldehydes and aryl-benzylic Grignard reagents as intermediates. For addition to carbonyl compounds, the use of lithium halides as an additive enhanced the efficiency of the reaction. Copyright
- Murai, Toshiaki,Morikawa, Kenta,Maruyama, Toshifumi
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p. 13112 - 13119
(2013/10/01)
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- C-S bond cleavage in aromatic sulfide radical cations
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The results of our recent studies of the structural effects on the C-S bond fragmentation process of aromatic sulfur radical cations are reported.
- Lanzalunga, Osvaldo
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p. 322 - 330
(2013/07/25)
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- Rhodium(I)/diene-catalyzed addition reactions of arylborons with ketones
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Rh(I)/diene-catalyzed addition reactions of arylboroxines/arylboronic acids with unactivated ketones to form tertiary alcohols in good to excellent yields are described. By using C2-symmetric (3aR,6aR)-3,6-diaryl-1,3a,4,6a- tetrahydropentalenes as ligands, the asymmetric version of such an addition reaction, with up to 68% ee, was also realized.
- Liao, Yuan-Xi,Xing, Chun-Hui,Hu, Qiao-Sheng
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supporting information; experimental part
p. 1544 - 1547
(2012/06/05)
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- Ni-catalysed, domino synthesis of tertiary alcohols from secondary alcohols
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The use of in situ generated (NHC)-Ni catalytic species (NHC = N-heterocyclic carbene) allows for the synthesis, in short reaction times, of a variety of tertiary alcohols from secondary alcohols through a domino oxidation-addition protocol.
- Berini, Christophe,Navarro, Oscar
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p. 1538 - 1540
(2012/02/16)
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- Added-metal-free catalytic nucleophilic addition of Grignard reagents to ketones
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On the basis of the investigation of the combinational effect of quaternary ammonium salts and organic bases, an added-metal-free catalytic system for nucleophilic addition reactions of a variety of Grignard reagents to diverse ketones in THF solvent has been developed to produce tertiary alcohols in good to excellent yields. By using tetrabutylammonium chloride (NBu4Cl) as a catalyst and diglyme (DGDE) as an additive, this system strongly enhances the efficiency of addition at the expense of enolization and reduction. NBu 4Cl should help to shift the Schlenk equilibrium of Grignard reagents to the side of dimeric Grignard reagents to favor the additions of Grignard reagents to ketones via a favored six-membered transition state to form the desired tertiary alcohols, and DGDE should increase the nucleophilic reactivities of Grignard reagents by coordination. This catalytic system has been applied in the efficient synthesis of Citalopram, an effective U.S. FDA-approved antidepressant, and a recyclable version of this catalytic synthesis has also been devised.
- Zong, Hua,Huang, Huayin,Liu, Junfeng,Bian, Guangling,Song, Ling
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experimental part
p. 4645 - 4652
(2012/07/03)
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- Iron-catalyzed pinacol coupling of aryl ketones with a phenyltitanium reagent: A new type of catalytic reaction
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A reaction of aryl ketones with phenyltitanium triisopropoxide ([PhTi(Oi-Pr)3]) in the presence of [Fe(acac)3] as a catalyst (1 mol%) gave the corresponding pinacols in high yields. The catalytic cycle of this process involves an iron-catalyzed disproportionation of [PhTi(Oi-Pr) 3] into biphenyl and a lowvalent titanium species.
- Hayashi, Tamio,Sasaki, Keigo
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scheme or table
p. 492 - 494
(2011/06/25)
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- Efficient and selective oxidative decarboxylation of arylcarboxylic acids into the corresponding aldehydes and ketones using K5Co IIIW12O40 as a green oxidant under microwave and conventional heating
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The oxidative decarboxylation of various α-aryl- and α, α-arylcarboxylic acids having electron-donating and electronwithdrawing groups by using a stoichiometric amount of potassium 12-tungstocobaltate(III), K5CoIIIW12O40, in 50% aqueous acetonitrile solution resulted in the corresponding aldehydes and ketones in high yields within short reaction times under microwave irradiation. This transformation was also carried out under the conventional heating conditions which produced the corresponding aldehydes and ketones in relatively longer reaction times. The arylacetic acids with electron-withdrawing substituents required longer reaction times and produced lower yields. In contrast to arylacetic esters which were inert toward decarboxylation, the sodium arylacetates were decarboxylated in shorter times with yields better than those of the parent acids.
- Farhadi,Ansari
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experimental part
p. 470 - 476
(2012/06/18)
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- Synthesis and application of 2,6-bis(trifluoromethyl)-4-pyridyl phosphanes: The most electron-poor aryl phosphanes with moderate bulkiness
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The poor will be rich: BFPy phosphanes (see scheme) mimic the electronic and steric characters of P(C6F5)3 and PPh 3, respectively. These novel ligands showed a large ligand acceleration effect on Stille coupling, the Rh-catalyzed 1,2-addition of aryl boronic acid to unactivated ketones and the asymmetric arylation of N-tosylimine using phenylboronic acid. Copyright
- Korenaga, Toshinobu,Ko, Aram,Uotani, Kotaro,Tanaka, Yuki,Sakai, Takashi
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supporting information; experimental part
p. 10703 - 10707
(2012/01/04)
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- Concerning the deprotonation of the trimethylsulfonium ion by the dimethylsulfinyl anion
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As shown by deuterium labelling experiments, the deprotonation of the trimethylsulfonium ion (1) by the dimsyl anion (8) is accompanied by extensive hydrogen exchange. This cannot be explained by an acid-base equilibrium between the trimethylsulfonium ion (1) and the dimsyl anion (8) on one side and dimethylsulfonium methylide (2) and DMSO on the other side, because for thermodynamic reasons this process is irreversible due to the limited life-time of 2. Therefore, the isotopic exchange that accompanies the deprotonation is an indicator of a more complex deprotonation process. It is suggested that in a kinetically controlled reaction, a proton of 1 is transferred to the O-atom of 8 rather than to the carbanionic centre. This means that instead of DMSO, its tautomer, hydroxy-methylsulfonium methylide (10), is obtained in the deprotonation process. Similarly, in the acid-base interaction between DMSO and its conjugate base 8, the formation of the DMSO tautomer 10 is kinetically favoured. The intermediate 10 produced in this way transfers a DMSO-derived proton to 1 when it intervenes in the back reaction 10 + 2 → 8 + 1. An alternative mechanism based on methyl group exchange between 1 and 8 could be excluded by a 13C-labelling experiment. The hydrogen exchange according to the suggested scenario is taking place in competition with the reaction of dimethylsulfonium methylide (2) with electrophilic substrates. This explains the different degrees of isotopic exchange when compounds of different electrophilicities are used to scavenge 2 from the deprotonation-hydrogen distribution equilibria.
- Haiss, Peter,Zeller, Klaus-Peter
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experimental part
p. 7748 - 7754
(2011/12/03)
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- Alkoxymagnesium iodide complexes
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The complexes R(Ph)MeCOMg(Et2O)I [1, R = Me (a), Ph (b)] were obtained by the reaction of R(Ph)C=O with MeMgI in diethyl ether in good yields. Crystallisation of 1 from acetonitrile resulted in single crystals of di- and trinuclear complexes I2(μ-OCPhMe2)2Mg(MeCN) 4 (2) and {2[I(MeCN)Mg(μ-OCPh2Me)2Mg(MeCN)I] (3) × [I(MeCN)Mg(μ-OCPh2Me)2Mg(μ-OCPh 2Me)2Mg(MeCN)I] (4) × 2CH2Cl2} in which the metal centres are linked by alkoxy substituents. The thermal decomposition of the complexes 1 was studied by successive detection of the EI mass spectra of diethyl ether, the olefins 5, the tertiary alcohols 6, and the formal olefin dimers 7. The complexes R1(Ph)MeCOMg(Et2O)I [1, R1 = Me (a), Ph (b)] are obtained by the reaction of R 1(Ph)C=O with MeMgI in diethyl ether in good yields. Crystallisation of 1 from acetonitrile results in single crystals of di- and trinuclear complexes (2, 3 and 4) in which the metal centres are linked by alkoxy substituents. The thermal decomposition of the complexes 1 is monitored by mass spectral detection of the decomposition products. Copyright
- Haiss, Peter,Kuhn, Annette,Kuhn, Norbert,Maichle-Moessmer, Caecilia,Laufer, Stefan,Steimann, Manfred,Zeller, Klaus-Peter
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scheme or table
p. 3284 - 3287
(2011/09/21)
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- Direct synthesis of anti -1,3-diols through nonclassical reaction of aryl grignard reagents with isopropenyl acetate
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A series of symmetrical aromatic 1,3-diols were efficiently synthesized from substituted aryl Grignard reagents and isopropenyl acetate in a one-step reaction that formed anti products as the major species. Both experimental and theoretical studies suggested that the reaction involves the formation of a relatively stable intermediate E containing a six-membered ring from intermediate A. The stereoselectivity of the reactions and the molecular structure of the products were confirmed by NMR spectroscopy, X-ray diffraction, and gas chromatography.
- Jiao, Yinchun,Cao, Chenzhong,Zhou, Zaichun
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supporting information; experimental part
p. 180 - 183
(2011/03/19)
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- Concerning the reactivity of ptad with isomeric dienes: The mechanism of the Diels-Alder cycloaddition
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Cyclopropyl substituted dienes are employed as mechanistic probes in the triazolinedione Diels-Alder (DA) reaction. In aprotic and protic solvents, apart from the DA adducts that bear an intact cyclopropyl group, complicated and rearranged products are also obtained. These results provide solid evidence for the involvement of an open intermediate with a lifetime greater than 2 x 10 -12 s.
- Alberti, Mariza N.,Orfanopoulos, Michael
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supporting information; scheme or table
p. 1659 - 1662
(2009/09/07)
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- Efficient chemoselective addition of grignard reagents to carbonyl compounds in 2-methyltetrahydrofuran
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Compared with tetrahydrofuran (THF) as a solvent for the addition reactions between Grignard reagents and carbonyl compounds 2-methyltetrahydrofuran affords the corresponding adducts in higher yields with higher chemoselectivities. Moreover, 2-methyltetrahydrofuran can be readily recycled and reused, which lowers the cost of the process and makes the reaction greener.
- Zhong, Weihui,Wu, Yaotiao,Zhang, Xingxian
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experimental part
p. 370 - 373
(2009/12/25)
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- APPARATUS AND METHOD FOR CARRYING OUT MULTIPLE REACTIONS
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The invention provides methods and an apparatus useful for site-isolating reagents or catalysts during chemical reactions. The methods and apparatus are useful for carrying out cascade or domino reactions.
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Page/Page column 5; 7
(2009/12/23)
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- Unusual reactions of Grignard reagents toward fluoroalkylated esters
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Fluorine-containing esters were demonstrated to be convenient substrates for construction of the corresponding ketones by low temperature reaction with Grignard reagents followed by warming up to 0 °C, while heating the mixture up to 80 °C readily promoted the reduction of the ketones obtained by the generated magnesium alkoxides whose mechanism was speculated as Meerwein-Ponndorf-Verley type reduction by computational technique.
- Yamazaki, Takashi,Terajima, Tsukasa,Kawasaki-Taskasuka, Tomoko
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p. 2419 - 2424
(2008/09/18)
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- The cyclopropyl group as a hypersensitive probe in the singlet oxygen ene reaction mechanism
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(Chemical Equation Presented) Cyclopropyl-substituted olefins are employed as mechanistic probes in the singlet oxygen-alkene ene reaction. In MeOH and aprotic solvents [CHCl3, (CH3)2CO, CH 3CN], only the allylic hydroperoxides bearing an intact cyclopropyl group are detected. The reaction mechanism is independent of solvent polarity. Our findings, to a certain experimental limit, exclude a biradical or dipolar intermediate.
- Alberti, Mariza N.,Orfanopoulos, Michael
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supporting information; experimental part
p. 2465 - 2468
(2009/05/27)
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- Cascade reactions using LiAlH4 and Grignard reagents in the presence of water
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(Figure Presented) Divided we stand, together we fall: Incompatible reagents, such as water and LiAlH4, Grignard, or cuprate reagents, can be site-isolated on either side of a polydimethylsiloxane (PDMS) thimble (see scheme; SDS = sodium docecyl sulfate) for cascade reactions. The hydrophobic nature of the PDMS membrane prohibits polar molecules, such as water, from diffusing across the membrane.
- Runge, M. Brett,Mwangi, Martin T.,Miller II, A. Lee,Perring, Mathew,Bowden, Ned B.
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p. 935 - 939
(2008/09/20)
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- Oxygen activation on metallic centers and oxidizing abilities of such oxygen
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It was shown that metallcontaining peroxides such as XOOOBu-t [X = (t-BuO)2Al, (t-BuO)3Ti] generate molecular oxygen in the electron-excited singlet state (1O2). These ozonides and η2-peroxocomplex Ph3Bi(η2O2) demonstrate high oxidative activity towards some classes of organic substances under mild conditions (20 °C).
- Zaburdaeva, Elena A.,Dodonov, Viktor A.,Stepovik, Larisa P.
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p. 1265 - 1268
(2008/02/04)
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- Catalytic photocarboxylation of 1,1-diphenylethylene with N,N,N′,N′-tetramethylbenzidine and carbon dioxide
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Photocarboxylation of 1,1-diphenylethylene with N,N,N′,N′-tetramethylbenzidine (TMB) in MeCN under bubbling of CO2 proceeded with high catalytic efficiency, giving 3,3-diphenylacrylic acid (DPA) and 3-hydroxy-3,3-diphenylpropionic acid (20). The turnover number (TON=(DPA+20)/TMB) reached 17. Similarly, 1-phenyl-1-cyclohexene yielded cis-2-acetamido-2-phenylcyclohexanecarboxylic acid with TON 5.9. As compared with related N,N-dimethylaniline derivatives, TMB is more resistant to photodecomposition, has the much larger absorbance in the S0→S1 transition, and has the lower quenching efficiency by CO2. Probably these factors are partly responsible for the high TON observed for TMB.
- Ito, Yoshikatsu
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p. 3108 - 3114
(2007/10/03)
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