- PALLADIUM-CATALYZED CROSS-COUPLING REACTIONS OF B-ALKYL-9-BBN OF TRIALKYLBORANES WITH ARYL AND 1-ALKENYL HALIDES
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The reactions of trialkylboranes or B-alkyl-9-BBN with aryl and 1-alkenyl halides take place readily in the presence of PdCl2(dppf) and sodium hydroxide or methoxide to afford alkylatad arenes and alkenes in excellent yields.
- Miyaura, Norio,Ishiyama, Tatsuo,Ishikawa, Masako,Suzuki, Akira
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- Microwave-assisted Suzuki-Miyaura cross-coupling of 2-alkyl and 2-alkenyl-benzo-1,3,2-diazaborolanes
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Nitrogen-based boronate esters, such as 2-octyl-benzo-1,3,2-diazaborolane, 2-phenethyl-benzo-1,3,2-diazaborolane, and 2-{(1E)-hexenyl}-benzo-1,3,2- diazaborolane have been shown to be suitable coupling partners with arylhalides in microwave accelerated Suzuki cross-coupling reactions. Reaction yields of up to 89% were achieved. The use of a silicon group attached to the nitrogen atom, proved to enhance the reactivity of 2-octyl-benzo-1,3,2-diazaborolane.
- Hadebe, Siphamandla W.,Sithebe, Siphamandla,Robinson, Ross S.
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experimental part
p. 4277 - 4282
(2011/06/26)
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- Cobalt-catalyzed cross-coupling reactions of aryl bromides with alkyl grignard reagents
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Aryl bromides react with primary alkyl Grignard reagents in the presence of N,N,N′,N′-tetramethyl-1,3-propanediamine and catalytic amounts of cobalt(II) chloride and an N-heterocyclic carbene to yield the corresponding cross-coupling products in high yields. Copyright
- Hamaguchi, Hiroyuki,Uemura, Minoru,Yasui, Hiroto,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 1178 - 1179
(2011/02/28)
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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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- Highly active catalyst for the heterogeneous Suzuki-Miyaura reaction: Assembled complex of palladium and non-cross-linked amphiphilic polymer
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An assembled insoluble catalyst, PdAS, prepared from palladium ((NH 4)2PdCl4 (1)) and non-cross-linked amphiphilic copolymer poly(N-isopropylacrylamide-co-4-diphenylstyrylphosphine) (2) was developed. It was found that PdAS is an excellent catalyst for the Suzuki-Miyaura reaction on three points: (1) The use of 8 × 10 -7 to 5 × 10-4 mol equiv of PdAS afforded the coupling products efficiently after easy workup, with the turnover number reaching up to 1 250 000. (2) The catalyst was reusable many times without loss of catalytic activity. (3) PdAS showed good stability in any reaction medium (i.e., water or aqueous or anhydrous organic solvents). Analytical study of PdAS indicates that the phosphines in 2 coordinate to palladium to form PdCl2(PPh2Ar)2 species.
- Yamada, Yoichi M. A.,Takeda, Koji,Takahashi, Hideyo,Ikegami, Shiro
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p. 7733 - 7741
(2007/10/03)
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- Metal cation-exchanged montmorillonite (Mn+-mont)-catalysed aromatic alkylation with aldehydes and ketones
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The alkylation of aromatic compounds with aldehydes and ketones in the presence of a variety of metal cation-exchanged montmorillonites (Mn+-mont; Mn+ = Zr4+, Al3+, Fe3+, Zn2+, H+, Na+) has been investigated. Al3+- and Zr4+-Monts are revealed to be effective as catalysts, while no reaction takes place with Na+-mont. Al3+-Mont-catalysed alkylation of phenol with several aldehydes produces mainly or almost solely the corresponding gem-bis(hydroxyphenyl)alkanes (bisphenols) in good yields, while that with several ketones affords selectively the corresponding alkylphenols in moderate to good yields. The alkylation always occurs at the carbonyl carbon without any skeletal rearrangement and the kind of products depends much on the steric hindrance of an electrophilic intermediary carbocation. The alkylation of anisole, veratrole and p-cresol proceeds well, while that of toluene, benzene, chlorobenzene and nitrobenzene scarcely occurs.
- Tateiwa, Jun-Ichi,Hayama, Ei,Nishimura, Takahiro,Uemura, Sakae
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p. 1923 - 1928
(2007/10/03)
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- Synthesis of 1-Arylalk-2-enes and 1-Arylalkanes via Friedel-Crafts Alkylation with Allylic Alcohols Catalysed by an Acidic Clay
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Moderately activated benzenoid compounds undergo alkylation with allylic alcohols in the presence of acidic K10 clay to give almost exclusively 1-arylalk-2-enes by attack at the terminal position of the intermediate allyl cation; catalytic hydrogenation yields the corresponding 1-arylalkanes.
- Smith, Keith,Pollaud, Guy M
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p. 3519 - 3520
(2007/10/02)
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- Palladium-Catalyzed Inter- and Intramolecular Cross-Coupling Reactions of B-Alkyl-9-borabicyclononane Derivatives with 1-Halo-1-alkenes or Haloarenes. Syntheses of Functionalized Alkenes, Arenes, and Cycloalkenes via a Hydroboration-Coupling Sequence
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The cross-coupling reaction of B-alkyl-9-borabicyclononanes (B-R-9-BBN), readily obtainable from alkenes by hydroboration, with 1-halo-1-alkenes or haloarenes in the presence of a catalytic amount of PdCl2(dppf) and bases, such as sodium hydroxide, potassium carbonate, and phosphate, gave the corresponding alkenes or arenes.Because the reaction is tolerant of a variety of functionalities on either coupling partner, stereochemically pure functionalized alkenes and arenes can be obtained under mild conditions.The utility of the reaction was demonstrated by the stereoselective synthesis of 1,5-alkadienes (7 and 8) and the extension of a side chain in a steroid (11).The hydroboration of haloalkadienes (12), followed by the intramolecular cross-coupling, gave a short-step procedure for synthesis of cycloalkenes, benzo-fused cycloalkenes, and exocyclic alkenes (14 and 16).
- Miyaura, Norio,Ishiyama, Tatsuo,Sasaki, Hirotomo,Ishikawa, Masako,Satoh, Makoto,Suzuki, Akira
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p. 314 - 321
(2007/10/02)
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