- Heterogeneous Nickel-Catalyzed Cross-Coupling between Aryl Chlorides and Alkyllithiums Using a Polystyrene-Cross-Linking Bisphosphine Ligand
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A polystyrene-cross-linking bisphosphine ligand PS-DPPBz was used for Ni-catalyzed cross-coupling with organolithiums. A bench-stable precatalyst [NiCl2(PS-DPPBz)] enabled efficient coupling reactions between aryl chlorides and alkyllithiums. The heterogeneous Ni system showed good reusability. (Figure presented.).
- Yamazaki, Yuki,Arima, Nozomi,Iwai, Tomohiro,Sawamura, Masaya
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supporting information
p. 2250 - 2254
(2019/03/21)
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- A general palladium catalyst system for suzuki-miyaura coupling of potassium aryltrifluoroborates and aryl mesylates
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(Figure presented) The first general examples of palladium-catalyzed Suzuki-type cross-coupling of aryl and heteroaryl mesylates with potassium aryl and heteroaryltrifluoroborates are presented. In addition to biaryl couplings, the cross-coupling reactions of aryl mesylates with alkyl and vinyltrifluoroborate salts have also been successfully accomplished.
- Chow, Wing Kin,So, Chau Ming,Lau, Chak Po,Kwong, Fuk Yee
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supporting information; scheme or table
p. 5109 - 5112
(2010/09/05)
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- Effect of solvent on the lithium-bromine exchange of aryl bromides: Reactions of n-butyllithium and tert-butyllithium with 1-bromo-4-tert- butylbenzene at 0 °C
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The outcome of reactions of 1-bromo-4-tert-butylbenzene (1), a representative aryl bromide, with n-BuLi or t-BuLi at 0 °C in a variety of solvent systems has been investigated. The products of reactions of 1 with n-BuLi vary significantly with changes in solvent composition: 1 does not react with n-BuLi in pure heptane; the exchange reaction to give (4-tert-butylphenyl) lithium, which is slow in pure diethyl ether, is virtually quantitative in heptane containing a small quantity of THF; and the reaction of 1 with n-BuLi in THF leads to considerable coupling. Lithium-bromine exchange is the virtually exclusive outcome of reactions of 1 with t-BuLi in every solvent studied except pure heptane: the presence of a small quantity of any of a variety of structurally diverse ethers (Et2O, THF, THP, MTBE) in the predominantly hydrocarbon medium affords (4-tert-butylphenyl)lithium, assayed as tert-butylbenzene, in yields exceeding 97%. The only side products observed from reactions of 1 with t-BuLi are small amounts of benzyne-derived hydrocarbons.
- Bailey, William F.,Luderer, Mark R.,Jordan, Kevin P.
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p. 2825 - 2828
(2007/10/03)
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- Stille cross-coupling of activated alkyltin reagents under "ligandless" conditions
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(Chemical Equation Presented) Monoalkyltins activated by a fluoride source are shown to be as reactive as their vinyl or aryl homologues in the Stille coupling reaction, thus providing an easy entry into the pallado-catalyzed formation of Csp3-Csp2 bonds. In addition to this uncommon reactivity, this methodology holds several advantages such as (i) a quantitative preparation of stable and easy to handle alkyltin reagents 2, (ii) a simplified coupling procedure without any phosphine added ligand under neutral conditions, and (iii) a facile purification step of the organic products from the inorganic nontoxic tin byproducts.
- Herve, Agnes,Rodriguez, Alain L.,Fouquet, Eric
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p. 1953 - 1956
(2007/10/03)
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- Tetraphosphine/palladium catalysed Suzuki cross-coupling reactions of aryl halides with alkylboronic acids
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Through the use of [PdCl(C3H5)]2/cis,cis, cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides and chlorides undergoes Suzuki cross-coupling with alkylboronic acids in good yields. Several alkyl substituents such as ethyl, n-butyl, n-octyl, isobutyl or 2,2-dimethylpropyl on the alkylboronic acids have been successfully used. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore, this catalyst can be used at low loading, even for reactions of sterically hindered aryl bromides.
- Kondolff, Isabelle,Doucet, Henri,Santelli, Maurice
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p. 3813 - 3818
(2007/10/03)
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- Catalyst for aromatic C—O, C—N, and C—C bond formation
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The present invention is directed to a transition metal catalyst, comprising a Group 8 metal and a ligand having the structure wherein R, R′ and R″ are organic groups having 1-15 carbon atoms, n=1-5, and m=0-4. The present invention is also directed to a method of forming a compound having an aromatic or vinylic carbon-oxygen, carbon-nitrogen, or carbon-carbon bond using the above catalyst. The catalyst and the method of using the catalyst are advantageous in preparation of compounds under mild conditions of approximately room temperature and pressure.
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- Air stable, sterically hindered ferrocenyl dialkylphosphines for palladium-catalyzed C-C, C-N, and C-O bond-forming cross-couplings
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Pentaphenylferrocenyl di-tert-butylphosphine has been prepared in high yield from a two-step synthetic procedure, and the scope of various cross-coupling processes catalyzed by complexes bearing this ligand has been investigated. This ligand creates a remarkably general palladium catalyst for aryl halide amination and for Suzuki coupling. Turnovers of roughly 1000 were observed for aminations with unactivated aryl bromides or chlorides. In addition, complexes of this ligand catalyzed the formation of selected aryl ethers under mild conditions. The reactions encompassed electron-rich and electron-poor aryl bromides and chlorides. In the presence of catalysts containing this ligand, these aryl halides coupled with acyclic or cyclic secondary alkyl- and arylamines, with primary alkyl- and arylamines, and with aryl- and primary alkylboronic acids. These last couplings provide the first general procedure for reaction of terminal alkylboronic acids with aryl halides without toxic or expensive bases. The ligand not only generates highly active palladium catalysts, but it is air stable in solution and in the solid state. Palladium(0) complexes of this ligand are also air stable as a solid and react only slowly with oxygen in solution.
- Kataoka, Noriyasu,Shelby, Quinetta,Stambuli, James P.,Hartwig, John F.
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p. 5553 - 5566
(2007/10/03)
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- Stereoselective cyclopropanation and ring-opening: Application to the synthesis of pure (S)-2-methyl-3-arylpropylamines
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Stereoselective catalytic and stoichiometric cyclopropanation of styrenes 3a,3b was studied; the stoichiometric method turned out superior in the terms of enantioselectivity. The intermediate carboxymethyl cyclopropane 11a,11b, obtained on reduction of carbethoxy derivatives 4a,4b, were hydrogenolyzed to (S)-1,3-substituted-2-methylpropanes 15a,15b. The highest conversion and regioselectivity was obtained with 3% Pd/C as the catalyst. The final steps, chlorination of alcohol 15a into 19a, and alkylation of cyclic sec amines were already demonstrated by us (ref. 2c) to afford (S)-(- )-2-(4-tert-butylphenyl)-1-cis-2,6-dimethylmorpholyl)propane (S-1a) and (S)- (-)-2-(4-tert-butylphenyl)-1-piperidylpropane (S-2a), the (S)-enantiomers of two systemic fungicides presently commercialized as racemates, without any lost of enantiomeric purity.
- Roje, Marin,Vinkovic, Vladimir,Sunjic, Vitomir,Solladie-Cavallo, Arlette,Diep-Vohuule, Anh,Isarno, Thomas
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p. 9123 - 9128
(2007/10/03)
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- Selective Preparation. 30. A Convenient Preparation of 5,13-Di-tert-butyl-8,16-disubstituted-metacyclophanes and Their Trans-tert-butylation and Halogenation Reactions
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The preparation of 5,13-di-tert-butyl-8,16-disubstituted-metacyclophanes (16a-k) from the corresponding 4-substituted-tert-butylbenzenes was described.The AlCl3-CH3NO2-catalyzed trans-tert-butylation of 5,13-di-tert-butyl-8,16-dimethylmetacyclophane (16b) in benzene afforded 8,16-dimethylmetacyclophane (28a) in good yield.However, the similar reaction of diethyl derivative 16c gave only a complex mixture of products.Treatment of 16b and 28a with NBS in CCl4 afforded the corresponding dibromides 38 and 39 in 86percent and 95percent yields, respectively.The bromination of 16b and 16c with bromine in CCl4 afforded the corresponding anti-10b,10c-dialkyl-4,5,9,10-tetrabromo-2,7-di-tert-butyl-10b,10c-dihydropyrenes 41a and 41b in good yields, respectively.However, it was also found that the bromination of 16b and 16c in the presence of Fe powder in the same solvent afforded 4,5,9,10-tetrabromo-2,7-di-tert-butylpyrene (40) in good yield in all cases.On the other hand, the bromination of 28a with bromine in the presence of Fe powder gave 2,7-dimethyl-3,6,8,11-tetrabromo-4,5,9,10-tetrahydropyrene (42).The reaction pathway of the bromination of 16 is discussed.
- Tashiro, Masashi,Yamato, Takehiko
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p. 1543 - 1552
(2007/10/02)
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