- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0085-0088
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
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Nucleophilic addition reactions of organometallic reagents to carbonyl compounds for carbon-carbon bond construction have played a pivotal role in modern chemistry. However, this reaction's reliance on petroleum-derived chemical feedstocks and a stoichiometric quantity of metal have prompted the development of many carbanion equivalents and catalytic metal alternatives. Here, we show that naturally occurring carbonyls can be used as latent alkyl carbanion equivalents for additions to carbonyl compounds, via reductive polarity reversal. Such 'umpolung' reactivity is facilitated by a ruthenium catalyst and diphosphine ligand under mild conditions, delivering synthetically valuable secondary and tertiary alcohols in up to 98% yield. The unique chemoselectivity exhibited by carbonyl-derived carbanion equivalents is demonstrated by their tolerance to protic reaction media and good functional group compatibility. Enantioenriched tertiary alcohols can also be accessed with the aid of chiral ligands, albeit with moderate stereocontrol. Such carbonyl-derived carbanion equivalents are anticipated to find broad utility in chemical bond formation.
- Wang, Haining,Dai, Xi-Jie,Li, Chao-Jun
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p. 374 - 378
(2017/04/03)
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- On the effect of backbone modifications in 3,3-dimethyl-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxole
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We report on the effect of small side-chain modifications to the structure of 3,3-dimethyl-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxole (1b) on its reactivity, as expressed by the initial rate v0 in a model reaction, and show how the latter can be successfully correlated to an easily determined physical parameter p, a 13C NMR chemical shift. The relationship v0~ p is already present in the simplest starting material devoid of the hypervalent bond and the iodine core and, therefore, presents an interesting approach towards the future scaffold-optimization of this class of reagents. The reactivity of hypervalent-iodine-based trifluoromethylating agents, as expressed by the initial rate v0 in a model reaction, correlates to an easily determined physical parameter p, a 13C NMR chemical shift.
- Santschi, Nico,Matthey, Coraline,Schwenk, Rino,Otth, Elisabeth,Togni, Antonio
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supporting information
p. 1925 - 1931
(2015/03/18)
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- Introducing deep eutectic solvents to polar organometallic chemistry: Chemoselective addition of organolithium and grignard reagents to ketones in air
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Despite their enormous synthetic relevance, the use of polar organolithium and Grignard reagents is greatly limited by their requirements of low temperatures in order to control their reactivity as well as the need of dry organic solvents and inert atmosphere protocols to avoid their fast decomposition. Breaking new ground on the applications of these commodity organometallics in synthesis under more environmentally friendly conditions, this work introduces deep eutetic solvents (DESs) as a green alternative media to carry out chemoselective additions of ketones in air at room temperature. Comparing their reactivities in DES with those observed in pure water suggest that a kinetic activation of the alkylating reagents is taking place, favoring nucleophilic addition over the competitive hydrolysis, which can be rationalized through formation of halide-rich magnesiate or lithiate species. Turning lithium green: A new protocol for the selective addition of Grignard and organolithium reagents to ketones in green, biorenewable, and deep eutectic solvents (DESs) is reported. The protocol establishes a bridge between main-group organometallic compounds and green solvents (ChCl=choline chloride; see picture). The DESs are superior reaction media for highly polar organometallic compounds.
- Vidal, Cristian,Garcia-Alvarez, Joaquin,Hernan-Gomez, Alberto,Kennedy, Alan R.,Hevia, Eva
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supporting information
p. 5969 - 5973
(2014/06/10)
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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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- Kinetic resolution of hydroperoxides with enantiopure phosphines: Preparation of enantioenriched tertiary hydroperoxides
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An efficient reductive kinetic resolution strategy capable of accessing optically active tertiary hydroperoxides is reported. Readily accessible tertiary hydroperoxides are resolved with commercially available (R)- or (S)-xylyl-PHANEPHOS with selectivity factors as large as 37. The resulting bis(phosphine oxide) can be recycled in high yields. The isolated mono(phosphine oxide) intermediate resolved hydroperoxides with the same selectivity as the parent bisphosphine. Copyright
- Driver, Tom G.,Harris, Jason R.,Woerpel
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p. 3836 - 3837
(2008/02/13)
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- An effect of application of chiral aluminium alkoxides and amides as adducts to zirconium catalyzed carbo- and cycloalumination of olefins
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This paper is dedicated to a study of properties of the following novel optically active organoaluminium compounds (OACs): (1S,2S)-l,7,7-trimethyl-2-[(dialkylalumina)oxy]-bicyclo[2.2.1]heptanes and (1S)-N-(dialkylalumina)-6,7-dimethoxy-1-methyl-1,2,3,4 -tetrahydroisoquinolines. The synthesis of the chiral OACs was carried out in the reaction of either natural camphor or salsolidine with both AlEt3 and i-Bu2AlH. The main goal of the research was to investigate the stereodifferentiating activity of the chiral OACs in the olefin carbo- and cycloalumination reactions, catalyzed by Cp2ZrCl2.
- Khalilov, Leonard M.,Parfenova, Ludmila V.,Pechatkina, Svetlana V.,Ibragimov, Askhat G.,Genet, Jean P.,Dzhemilev, Usein M.,Beletskaya, Irina P.
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p. 444 - 453
(2007/10/03)
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- Samarium(II) triflate as a new reagent for the grignard-type carbonyl addition reaction
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On treatment of a THF solution of Sm(OTf)3 with 1 equiv of an organolithium or organomagnesium reagent at ambient temperature, the purple or deep green solution of the divalent samarium triflate [Sm(OTf)2] was readily obtained. For this preparation, s-BuLi was the most effective as was evidenced by the reduction of 2-phenylethyl iodide in the presence of HMPA. The Sm(OTf)2 reagent mediated the Grignard-type reaction effectively in THF/HMPA; alkylation and allylation of ketones or aldehydes with alkyl, allyl, or benzyl halides proceeded via organosamarium intermediates. Diastereoselectivity of the samarium-Grignard reaction was examined using 2-methylcyclohexanone, 4-tert-butylcyclohexanone, and 2-phenylpropanal and was found to be higher in each case than that with SmI2. With 2-methylcyclohexanone, for example, Sm(OTf)2 gave the greatest ratio of axial alcohol:equatorial alcohol = 99:1, and SmI2 gave a ratio of 91:9. Halides containing an ester or a silyl group were reactive in the Reformatsky- or Peterson-type reaction, respectively, using the Sm(OTf)2 reagent.
- Fukuzawa, Shin-Ichi,Mutoh, Keisuke,Tsuchimoto, Teruhisa,Hiyama, Tamejiro
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p. 5400 - 5405
(2007/10/03)
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- Highly enantioselective addition of primary alkyl Grignard reagents to carbocyclic and heterocyclic arylketones in the presence of magnesium TADDOLate preparative and mechanistic aspects
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In the presence of equimolar amounts of the Mg alkoxide from α,α,α',α'-tetraphenyl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol (a TADDOL) primary Grignard reagents (Et, Pr, Bu, Oct, 3-butenyl) add to carbo- and heteroaromatic methyl ketones in THF at -100°C to give tertiary alcohols of enantiomeric excesses reaching values above 98%. The scope and limitation of the method are investigated. The reaction, which occurs in a vigorously stirred heterogeneous mixture, give best results in the absence of steric hindrance of the reacting centers; Grignard reagents made from alkyl bromides are superior to those obtained from chlorides; there is a perfect linear relationship between the ee of the TADDOL and of the product 2-phenyl-2-decanol; those tertiary alcohols of which the absolute configuration is known, are formed by nucleophilic attack from the Re face of the keto carbonyl groups. Three tentative mechanistic models for the stereochemical course of the reaction are discussed.
- Weber, Beat,Seebach, Dieter
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p. 6117 - 6128
(2007/10/02)
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- Preparation of Samarium(II) Triflate and It Mediated Grignard-type Reaction. In Situ Formation and Reaction of New Organosamarium Reagents
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Samarium(II) triflate was readily prepared by reaction of samarium(III) triflate with sec-butyllithium at room temperature in THF.Its reducing ability was examined by pinacol coupling of carbonyl compounds.Sm(OTf)2 mediated Grignard-type reaction in THF-HMPA effectively; alkylation and allylation of ketones or aldehydes by simple alkyl, allyl, and benzyl halides proceeded via organosamarium intermediates.
- Fukuzawa, Shin-ichi,Tsuchimoto, Teruhisa,Kanai, Takeshi
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p. 1981 - 1984
(2007/10/02)
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- Bimolecular Formation of Radicals by H-Transfer, 7. - Bimolecular Formation of Radicals via H-Transfer with Catalysis by 7H-Benzanthracene
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The transfer hydrogenation of α-methylstyrene (2) by 9,10-dihydroanthracene (1) (DHA) with 7H-benzanthracene (8) as a catalyst proceeds already at 210-260 deg C.Isotopic labeling, ESR spectroscopy, radical clock experiments, solvents effects, and thermochemical calculations support the postulated stepwise radical mechanism induced by bimolecular formation of radicals. - Key Words: Molecule-induced radical formation, kinetics of / Catalysis / ESR spectroscopy / Radical clock / Isokinetic relationship
- Gerst, Matthias,Morgenthaler, Jens,Ruechardt, Christoph
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p. 691 - 696
(2007/10/02)
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- Novel Synthetic Route to Aryl Alkanes from Aromatic Aldehydes and Ketones. Novel Geminal Dialkylation of the Carbonyl Group of Aromatic Aldehydes and Ketones
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Benzyl-lithiums, readily available from benzyl methyl selenides and alkyl-lithiums, are efficiently alkylated; this reaction allows the geminal dialkylation of the carbonyl groups of aromatic aldehydes and ketones and the geminal aryl-alkylation of aliphatic analogues.
- Krief, Alain,Clarembeau, M.,Barbeaux, Ph.
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p. 457 - 458
(2007/10/02)
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- Thermolabile Hydrocarbons, XX. Synthesis, Structure, and Strain of Sym. Tetraalkyl-1,2-diarylethanes
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The syntheses of 18 1,1,2,2-tetraalkyl-1,2-diarylethanes 1 - 4 by dimerisation procedures starting with 10 - 13 are reported.In the absence of p-substituents X and with increasing alkyl side chains the α,p-dimers 6 or their aromatic counter parts 7 are obtained besides or instead of 1.The relationships between strain enthalpy Hs, bond lengths, bond angles, torsional angles, and rotational barrier are discussed on the basis of force field calculations.They are supported by two additional experimental structure determinations by X-ray diffraction.
- Kratt, Guenter,Beckhaus, Hans-Dieter,Lindner, Hans Joerg,Ruechardt, Christoph
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p. 3235 - 3263
(2007/10/02)
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- COMPLEXES OF TRANSITION METALS IN THE CHEMISTRY OF CONJUGATED SYSTEMS. I. CATALYTIC ADDITION OF ORGANOMAGNESIUM AND ORGANOLITHIUM COMPOUNDS TO ENYNES AND THEIR DERIVATIVES
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Hydrocarbons with a conjugated system of double and triple bonds are capable of catalytic addition of arylmagnesium halides and aryllithiums at the triple bond in the presence of the salts and complexes of transition metals of group VIII.The β-diketonate complexes of Ni(II) and Fe(III) have the greatest activity.In the case of aryllithiums uncatalyzed addition reactions occur as well.Under the same conditions aliphatic Grignard reagents and alkyllithiums give a complex mixture of addition, reduction and oligomerizatin products.The direction of addition is determined solely by the character of substitution in the enyne system.The product yields are also determined by the nature of the metal and of the ligands in the catalyst and by the character of the organomagnesium and organolithium compound.The effect of polar and steric factors of the substituents at the triple bond in the alkyl, aryl, and trialkylsilyl series leads to a change in the direction of coordination and to the formation of the products from addition at the double bond.
- Zubritskii, L. M.,Fomina, T. N.,Bal'yan, Kh. V.
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