- One-Pot Deoxygenation and Substitution of Alcohols Mediated by Sulfuryl Fluoride
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Sulfuryl fluoride is a valuable reagent for the one-pot activation and derivatization of aliphatic alcohols, but the highly reactive alkyl fluorosulfate intermediates limit both the types of reactions that can be accessed as well as the scope. Herein, we report the SO2F2-mediated alcohol substitution and deoxygenation method that relies on the conversion of fluorosulfates to alkyl halide intermediates. This strategy allows the expansion of SO2F2-mediated one-pot processes to include radical reactions, where the alkyl halides can also be exploited in the one-pot deoxygenation of primary alcohols under mild conditions (52-95% yield). This strategy can also enhance the scope of substitutions to nucleophiles that are previously incompatible with one-pot SO2F2-mediated alcohol activation and enables substitution of primary and secondary alcohols in 54-95% yield. Chiral secondary alcohols undergo a highly stereospecific (90-98% ee) double nucleophilic displacement with an overall retention of configuration.
- Epifanov, Maxim,Mo, Jia Yi,Dubois, Rudy,Yu, Hao,Sammis, Glenn M.
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p. 3768 - 3777
(2021/03/01)
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- Environmentally responsible, safe, and chemoselective catalytic hydrogenation of olefins: ppm level Pd catalysis in recyclable water at room temperature
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Textbook catalytic hydrogenations are typically presented as reactions done in organic solvents and oftentimes under varying pressures of hydrogen using specialized equipment. Catalysts new and old are all used under similar conditions that no longer reflect the times. By definition, such reactions are both environmentally irresponsible and dangerous, especially at industrial scales. We now report on a general method for chemoselective and safe hydrogenation of olefins in water using ppm loadings of palladium from commercially available, inexpensive, and recyclable Pd/C, together with hydrogen gas utilized at 1 atmosphere. A variety of alkenes is amenable to reduction, including terminal, highly substituted internal, and variously conjugated arrays. In most cases, only 500 ppm of heterogeneous Pd/C is sufficient, enabled by micellar catalysis used in recyclable water at room temperature. Comparison with several newly introduced catalysts featuring base metals illustrates the superiority of chemistry in water.
- Gallou, Fabrice,Gao, Eugene S.,Lipshutz, Bruce H.,Takale, Balaram S.,Thakore, Ruchita R.
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supporting information
p. 6055 - 6061
(2020/10/14)
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- Hydrogenation of Alkenes Catalyzed by a Non-pincer Mn Complex
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Hydrogenation of substituted styrenes and unactivated aliphatic alkenes by molecular hydrogen has been achieved using a Mn catalyst with a non-pincer, picolylphosphine ligand. This is the second reported example of alkene hydrogenation catalyzed by a Mn complex. Mechanistic studies showed that a Mn hydride formed by H2 activation in the presence of a base is the catalytically active species. Based on experimental and DFT studies, H2 splitting is proposed to occur via a metal-ligand cooperative pathway involving deprotonation of the CH2 arm of the ligand, leading to pyridine dearomatization.
- Rahaman, S. M. Wahidur,Pandey, Dilip K.,Rivada-Wheelaghan, Orestes,Dubey, Abhishek,Fayzullin, Robert R.,Khusnutdinova, Julia R.
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p. 5912 - 5918
(2020/10/30)
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- Efficient chemoselective reduction of nitro compounds and olefins using Pd-Pt bimetallic nanoparticles on functionalized multi-wall-carbon nanotubes
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We report the synthesis of novel Pd-Pt bimetallic nanoparticle catalysts using functionalized multi-wall carbon-nanotubes and utilization of them to reductions. The carbon nanotube-supported bimetallic nanoparticle catalysts showed improved activity in reduction reactions, compared with that of mono metal-supported catalysts. Under the optimized reaction conditions, various nitro compounds and alkenes were cleanly reduced at ambient temperature. Furthermore, this catalytic system exhibits excellent activity and high chemoselectivity for nitro compounds in the presence of other functional groups labile to hydrogenation. After the reaction, the catalysts could be collected through filtration, and reused for 10 times without any loss of catalytic activity.
- Kim, Eunsuk,Jeong, Han Saem,Kim, B. Moon
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- Catalytic study of heterobimetallic rhodium complexes derived from partially alkylated s-indacene in dehydrogenative silylation of olefins
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This work describes the catalytic study of heterobimetallic rhodium compounds derived from partially alkylated s-indacene in dehydrogenative silylation of olefins in order to elucidate as much as possible the effects of: solvent, temperature, chemical substrates, olefin effect, silane effect, and secondary metallic fragment. The rhodium complexes, anti-[Cp*Fe-s- Ic′-Rh(COD)] 1, anti-[Cp*Ru-s-Ic′-Rh(COD)] 2, and syn-[Cp*Ru-s-Ic′-Rh(COD)] 2′ (with s-Ic′: 2,6-diethyl-4,8-dimethyl-s-indaceneiide) were previously synthesized and characterized, and were compared with the catalytic activity of the complexes previously reported; monometallic [(COD)Rh-s-Ic′H] 3, and homobimetallic anti-[{(COD)Rh}2-s-Ic′] 4, and syn-[{(COD)Rh} 2-s-Ic′] 4′. The heterobimetallic complexes show a high activity and selectivity for the dehydrogenative silylation of styrene and these complexes show also the presence of a cooperative effect between both metallic centers, which is evidenced when compared with monometallic complex.
- Adams,Riviere,Riviere-Baudet,Morales-Verdejo,Dahrouch,Morales,Castel,Delpech,Manríquez,Chávez
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p. 266 - 274
(2013/11/19)
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- Iron-catalysed alkene hydrogenation and reductive cross-coupling using a bench-stable iron(II) pre-catalyst
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Operationally simple, iron-catalysed hydrogenation and reductive cross-coupling protocols have been developed using a bench-stable iron(ii) pre-catalyst. The hydrogenation of 18 alkenes (50-99%) and reductive cross-coupling of vinyl halides with aryl- and alkyl Grignard reagents (8 examples, 18-99%) is reported using 3 mol% pre-catalyst and hydrogen as stoichiometric reductant (1-50 bar).
- Frank, Dominik J.,Guiet, Lea,Kaeslin, Alexander,Murphy, Elliot,Thomas, Stephen P.
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p. 25698 - 25701
(2013/12/04)
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- Rhodium(I) acetylacetonato complexes containing phosphinoalkynes as catalysts for the hydroboration of vinylarenes
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Three novel rhodium(I) acetylacetonato (acac) complexes bearing phosphinoalkynes (Ph2PC≡C-t-Bu, Ph2PC≡ CPPh2, and Ph2PC≡CC≡CPPh2) have been prepared and characterized fully. Addition of B2cat3 (cat = 1,2-O2C6H4) to Rh(acac)(Ph 2PC≡C-t-Bu)2 (1a) led to zwitterionic Rh(η6-catBcat)(Ph2PC≡C-t-Bu)2 (2a), the first example of this type of compound to contain monodentate phosphine ligands. All new rhodium complexes have been investigated for their ability to catalyse the hydroboration of vinylarenes.
- Vogels, Christopher M.,Decken, Andreas,Westcott, Stephen A.
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p. 146 - 153
(2007/10/03)
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- Sedimentary Evidence for a Diaromatic Carotenoid with an Unprecedented Aromatic Substitution Pattern
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A novel diaryl isoprenoid (C40H66), possessing a 3,4,5-/2,3,6-trimethyl aromatic substitution pattern, which is attributed to a presently unknown strain of photosynthetic green sulfur bacteria, has been identified in a carbonaceous sedimentary rock.
- Hartgers, Walter A.,Damste, Jaap S. Sinninghe,Koopmans, Martin P.,Leeuw, Jan W. de
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p. 1715 - 1716
(2007/10/02)
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- Synthetic Methods and Reactions; 126. Trifluoromethanesulfonic Acid/Triethylsilane: A New Ionic Hydrogenation Reagent for the Reduction of Diaryl and Alkyl Aryl Ketones to Hydrocarbons
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Benzophenones (except for 4,4'-dialkoxy- and sterically hindered derivatives), certain acetophenones, and 1-indanone can be reduced to the corresponding hydrocarbons in good yields by reaction with trifluoromethanesulfonic acid and triethylsilane.
- Olah, George A.,Arvanaghi, Massoud,Ohannesian, Lena
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p. 770 - 772
(2007/10/02)
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- Structure of ω-Arylalkyl Radicals: A 13C CIDNP Investigation
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Thermolysis of a series of ω-arylalkanoyl m-chlorobenzoyl (and acetyl) peroxides at ca. 100 deg C in cyclohexanone and in hexachloroacetone was studied by using 13C chemically induced dynamic nuclear polarization.Analysis of the observed 13C polarizations indicate that all the three radicals (β-arylethyl, γ-arylpropyl and δ-arylbutyl) have open-chain structures with no evidence for aryl participation resulting in spirocycloalkylcyclohexadienyl radicals.
- Olah, George A.,Krishnamurthy, V. V.,Singh, Brij P.,Iyer, Pradeep S.
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p. 955 - 963
(2007/10/02)
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- A MILD REDUCTION OF BENZYL ALCOHOLS WITH DIPHOSPHORUS TETRAIODIDE
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On treatment with diphosphorus tetraiodide in boiling benzene, benzyl alcohols are smoothly reduced to parent hydrocarbons in good to moderate yields.
- Suzuki, Hitomi,Tani, Hiroyuki,Kubota, Hirohisa,Sato, Naofumi,Tsuji, Junko,Osuka, Atsuhiro
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p. 247 - 248
(2007/10/02)
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- Reductive Coupling of Aromatic Ketones by Low-valent Titanium Salts
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Reaction of sterically congested aromatic ketones with the McMurry reagent (4TiCl3, LiAlH4) in tetrahydrofuran yields is not only the olefins (E- and Z-isomers), but also the corresponding ethanes and some other products.We have studied the minor or non-normal products of this reaction.
- Bottino, Francesco,Finocchiaro, Paolo,Libertini, Emanuela,Reale, Antonino,Recca, Antonino
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- THE HYDROGENATION OF STYRENES BY HYDRIDOCOBALT TETRACARBONYL
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The rates of hydrogenation of several styrene derivatives by stoichiometric hydridocobalt tetracarbonyl were measured and compared.The relative rates are discussed in terms of conjugative and steric effects on the geminate radical pair mechanism.An improved method for determining HCo(CO)4 concentration is described.
- Roth, Jerome A.,Wiseman, Paul,Ruszala, Lois
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p. 271 - 276
(2007/10/02)
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- Sterically Hindered Olefins, VIII. Reaction of 1-Indanones with Low-valent Titanium Compounds. Steric Influence of Methyl Substituents in 1-(1-Indanyliden)indanes and 9-(9-Fluorenylidene)fluorenes
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Ketones 1a and b react with low-valent titanium salts to yield the trans-olefins 2a and b, respectively.From 1c the diene 4c is formed, probably via 2c.Ketone 1d is reduced to the hydrocarbon 7.Similarly the aromatic ketones 5 and 6 are reduced exclusively, yielding the hydrocarbons 8 and 9.While 10a shows coupling to 11a (94percent), ketone 10d does not react. - Preferred geometrics as well as strain energies are calculated using Allinger's force-field for 2, 3, and 11 (in all cases a-d).The calculated geometry of olefin 11a is compared with those known from the X-ray structure.
- Lenoir, Dieter,Lemmen, Peter
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p. 3112 - 3119
(2007/10/02)
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- Alkyltrifluoromethanesulphonates as alkylating reagents for aromatic compounds
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Methyl and ethyl trifluoromethanesulphonates (' triflates '), prepared by conventional routes involving either trifluoromethanesulphonic acid (' triflic acid ') or its anhydride, contain traces of triflic acid as an impurity, which catalyse their alkylation reactions with aromatic compounds. Pure methyl triflate, obtained from reaction between CH3l and CFS03Ag, does not alkylate p-cymene after several hours at 100 °C. Pure ethyl triflate, prepared by a similar method, is thermally less stable under these conditions, and alkylation takes place only after long induction periods during which some breakdown to triflic acid occurs. With aromatic substrates such as p-cymene or mesitylene the onset of alkylation is followed rapidly by the formation of isomerisation and disproportionation products. Benzyl triflate, prepared from PhCH2Br and CF3SO3Ag, alkylates p-cymene even at room temperature. The strong Lewis acids SbF5 and AlCl3 similarly catalyse alkylation reactions of methyl and ethyl triflates, but BF3, FeCl3, and SnCl4 are much less effective.
- Booth, Brian L.,Haszeldine, Robert N.,Laali, Khosrow
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p. 2887 - 2893
(2007/10/02)
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