- Oxime palladacycle-catalyzed Suzuki-Miyaura alkenylation of aryl, heteroaryl, benzyl, and allyl chlorides under microwave irradiation conditions
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A simple new protocol for the palladium-catalyzed Suzuki-Miyaura cross-coupling of organic chlorides under microwave irradiation is presented. Deactivated aryl and heteroaryl chlorides are efficiently cross-coupled with alkenylboronic acids and potassium alkenyltrifluoroborates using the 4,4′-dichlorobenzophenone oxime-derived palladacycle 1b as precatalyst in 0.1 to 0.5 mol% palladium loading, tris(tert-butyl)phosphonium tetrafluoroborate {[HP(t-Bu)3]BF4} as ligand, tetra-n-butylammonium hydroxide as cocatalyst, and potassium carbonate as base in N,N- dimethylformamide at 130°C under microwave irradiation conditions. Under these conditions, styrenes, stilbenes, and alkenylarenes are obtained in good to high yields, and with high regio- and diastereoselectivities in only 20 min. The reported protocol is also very efficient for the regioselective alkenylation of benzyl and allyl chlorides to afford allylarenes and 1,4-dienes. Copyright
- Civicos, Jose F.,Alonso, Diego A.,Najera, Carmen
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supporting information; experimental part
p. 1683 - 1687
(2011/09/19)
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- Palladium(0)-catalyzed direct cross-coupling reaction of allylic alcohols with aryl- and alkenylboronic acids
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Allylic alcohols can be used directly for the palladium(0)-catalyzed allylation of aryl- and alkenylboronic acids with a wide variety of functional groups. A triphenylphosphine-ligated palladium catalyst turns out to be most effective for the cross-coupling reaction and its low loading (less than 1 mol%) leads to formation of the coupling product in high yield. The Lewis acidity of the organoboron reagents and poor leaving ability (high basicity) of the hydroxyl group are essential for the cross-coupling reaction. The reaction process is atom-economical and environmentally benign, because it needs neither preparation of allyl halides and esters nor addition of stoichiometric amounts of a base. Furthermore, allylic alcohols containing another unsaturated carbon-carbon bond undergo arylative cyclization reactions leading to cyclopentane formation. The Royal Society of Chemistry.
- Tsukamoto, Hirokazu,Uchiyama, Tomomi,Suzuki, Takamichi,Kondo, Yoshinori
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supporting information; experimental part
p. 3005 - 3013
(2009/02/03)
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- Nickel-catalyzed cross-coupling reaction of allyl- and benzylzinc with alkenyl sulfides
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Alkenyl Sulfides can be utilized for nickel-catalyzed cross-coupling reactions with allyl- and benzylzinc reagents.
- Baba, Yoko,Toshimitsu, Akio,Matsubara, Seijiro
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scheme or table
p. 2061 - 2063
(2009/04/11)
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- Cross-coupling reaction of allylic and benzylic carbonates with organo[2-(hydroxymethyl)phenyl]dimethylsilanes
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The title reaction is found to proceed in the presence of a palladium catalyst and in the absence of any activator. Various functional groups are tolerated to give a diverse range of 1,4-diene and diarylmethane products, which are ubiquitous units of natural products and pharmaceuticals. Copyright
- Nakao, Yoshiaki,Ebata, Shiro,Chen, Jinshui,Imanaka, Hidekazu,Hiyama, Tamejiro
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p. 606 - 607
(2008/02/07)
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- Microwave-enhanced cross-coupling of allyl chlorides with vinyltrifluoroborates
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The allylation of potassium alkenyltrifluoroborates with allyl chloride via a palladium catalyzed cross-coupling reaction occurs rapidly under microwave irradiation. The allylation reaction produces 1,4-pentadienes in high yields.
- Kabalka, George W.,Dadush, Eric,Al-Masum, Mohammad
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p. 7459 - 7461
(2007/10/03)
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- The Palladium-Catalyzed Cross-Coupling Reaction of Organosilicon Compounds with Allylic Carbonates or Diene Monoxides
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The cross-coupling reaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst.The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon reagent.Likewise, diene monoxides also underwent cross-coupling with alkenyl- and arylfluorosilanes in moderate to high yields.
- Matsuhashi, Hayao,Asai, Satoshi,Hirabayashi, Kazunori,Hatanaka, Yasuo,Mori, Atsunori,Hiyama, Tamejiro
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p. 1943 - 1952
(2007/10/03)
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- Syntheses of 1,3- and 1,4-Dienes by the Oxidative Coupling of 1-Alkenylstannanes and 2-Alkenylstannanes in the Presence of Palladium Catalyst
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Treatment of 1-alkenylstannanes with tBuOOH in the presence of palladium catalyst gives 1,3-dienes.Cross coupling reaction between 1-alkenylstannanes and 2-alkenylstannanes provides 1,4-dienes selectively in good yields.
- Kanemoto, Shigekazu,Matsubara, Seijiro,Oshima, Koichiro,Utimoto, Kiitiro,Nozaki, Hitosi
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- ZUR BILDUNG METALLACYCLISCHER FUENFRINGVERBINDUNGEN: REGIOSELEKTIVITAET DER ADDITION VON ALKINEN AN ZIRCONOCENKOMPLEXE
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Metallacycles are formed upon thermolysis of (s-trans-η4-butadiene)zirconocene and binuclear (η2-aldehyde)zirconocene complexes or photolysis of diphenylzirconocene in the presence of t-butyl-, trimethylsilyl-, and phenyl-acetylene.From a surprising equally high preference for α-t-butyl- and -trimethylsilyl-substituted products as well as the statistically favoured 2,4-disubstituted metallacyclopentadienes formed from t-butyl- or trimethylsilyl-acetylene it is suggested, that the position of the substituents in the final product is predominantly determined by the coordination of the alkyne preceding the ring-closure reaction.In contrast to the thermally induced reactions the expected major product (2,5-disubstituted zirconacyclopentadiene) of the kinetically controlled cyclization reaction is formed upon photolysis of diphenylzirconocene in the presence of phenylacetylene.
- Skibbe, Volker,Erker, Gerhard
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