- Synthesis and transformations of 4-phenylethynyl- and 4-styrylpyrazolo[5,1-c][1,2,4]triazines
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[Figure not available: see fulltext.] Rearrangements of 3-tert-butyl-8-methyl-4-phenylethynyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazine derivatives by the action of bases led to the formation of aromatic (E)- or (Z)-4-styryl-functionalized compounds. At t
- Ivanov, Sergey M.,Koltun, Denis S.
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p. 656 - 665
(2021/07/02)
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- Tandem Suzuki-Miyaura coupling/acid-catalyzed cyclization between vinyl ether boronates and vinyl halides: A concise approach to polysubstituted furans
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Polysubstituted 2-(ω-hydroxyalkyl)furans were prepared by tandem Suzuki-Miyaura coupling/acid-catalyzed cyclization starting from appropriately substituted 3-haloallylic alcohols and dihydrofuran-, dihydropyran- or glycal-derived pinacol boronates.
- Butkevich, Alexey N.,Meerpoel, Lieven,Stansfield, Ian,Angibaud, Patrick,Corbu, Andrei,Cossy, Janine
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supporting information
p. 3840 - 3843
(2013/09/02)
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- Cu(II)-catalyzed aerobic hydroperoxidation of Meldrum's acid derivatives and application in intramolecular oxidation: A conceptual blueprint for O 2/H2 dihydroxylation
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Aerobic hydroperoxidation of Meldrum's acid derivatives via a Cu(II)-catalyzed process is presented. The mild reaction conditions are tolerant to pendant unsaturation allowing the formation of endoperoxides via electrophilic activation. Cleavage of the O-
- Krabbe, Scott W.,Do, Dung T.,Johnson, Jeffrey S.
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supporting information
p. 5932 - 5935
(2013/02/22)
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- Palladium-catalyzed coupling of propargylic carbonates with N-tosylhydrazones: Highly selective synthesis of substituted propargylic N-sulfonylhydrazones and vinylallenes
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An efficient palladium-catalyzed coupling of propargylic carbonates (1) with N-tosylhydrazones (2, 2′) has been carried out. A wide range of propargylic N-sulfonylhydrazones (3) and multisubstituted vinylallenes (4) can be obtained selectively by using either [PdCl2(CH3CN) 2] or [Pd2(dba)3] as catalysts. (dba=trans,trans-dibenzylideneacetone, dppp=propane-l,3- diylbis(diphenylphosphane), Ts=4-toluenesulfonyl.) Copyright
- Chen, Zi-Sheng,Duan, Xin-Hua,Wu, Lu-Yong,Ali, Shaukat,Ji, Ke-Gong,Zhou, Ping-Xin,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information; experimental part
p. 6918 - 6921
(2011/07/08)
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- Iron-catalyzed quick homocoupling reaction of aryl or alkynyl Grignard reagents using a phosphonium ionic liquid solvent system
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The iron-catalyzed homocoupling reaction of aryl Grignard reagent was completed very quickly when the reaction was carried out in a phosphonium salt ionic liquid solvent system at 0°C for 5 min. Using a similar reaction system, the first example of the iron-catalyzed homocoupling reaction of alkynyl Grignard reagents has also been accomplished using the ionic liquid technology.
- Kude, Keisuke,Hayase, Shuichi,Kawatsura, Motoi,Itoh, Toshiyuki
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experimental part
p. 397 - 404
(2012/01/13)
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- Tandem Zn-Brook rearrangement/ene-allene carbocyclization
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The addition of metalated alkynes to acylsilanes leads to the corresponding α-propargylsilanol derivatives. On addition of ZnBr2, Zn-promoted Brook rearrangements take place to produce the propargyl/allenylzinc bromides, which undergo cyclization to give functionalized carbocycles as single diastereoisomers. Wiley-VCH Verlag GmbH & Co. KGaA.
- Unger, Rozalia,Cohen, Theodore,Marek, Ilan
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experimental part
p. 1749 - 1756
(2009/08/17)
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- CLICKPHOSPHINES FOR TRANSITION METAL-CATALYZED REACTIONS
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Phosphine triazole ligand compounds, prepared through click chemistry, complex with transition metals to form transition metal-phosphine triazole ligand complexes. These complexes are useful catalysts in coupling reactions such as Suzuki-Miyaura coupling, Stille coupling, Negishi coupling, Sonagashira coupling, carbon-heteroatom bond-forming reactions (C-O and C-N), alpha alkylation of carbonyls, Heck coupling reactions, and hydrogenation reactions.
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Page/Page column 14
(2010/11/25)
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- Cascade reactions: Sequential homobimetallic catalysis leading to benzofurans and β,γ-unsaturated esters
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The concatenation between a Pd(0)-promoted deallylation catalytic cycle and a Pd(II)-promoted heterocyclization catalytic cycle (an example of what we have named "sequential homobimetallic catalysis") has been shown to occur starting from 1-(2-allyloxyphenyl)-2-yn-1-ols 1 to afford 2-benzofuran-2- ylacetic esters 2 and β,γ-unsaturated esters in high yields under carbonylative conditions. In view of the conceptual as well as the synthetic importance of the process, the mechanistic aspects and the synthetic scope of the reaction have been investigated in detail. All the experimental evidence is in agreement with the sequential homobimetallic mechanism, and the reaction has proven to be of general synthetic applicability.
- Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe,Costa, Mirco
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p. 1101 - 1109
(2007/10/03)
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- Reaction of an electrogenerated 'iminium cation pool' with organometallic reagents. Direct oxidative α-alkylation and -arylation of amine derivatives
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We have developed an efficient direct oxidative α-alkylation and -arylation of carbamates based on the 'cation pool' method. Grignard reagents, organozinc compounds, and organoaluminum compounds are effective as carbon nucleophiles toward iminium cation pools generated by low temperature electrolysis of carbamates.
- Suga, Seiji,Okajima, Masayuki,Yoshida, Jun-ichi
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p. 2173 - 2176
(2007/10/03)
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- Vinyl Cations in Organic Synthesis. Part 2. A Novel Synthesis of Methylene-1H-indenes (Benzofulvenes) by Cyclisation of Phenyl-substituted But-1-en-3-ynes
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A series of phenyl-substituted but-1-en-3-ynes has been prepared and their reactivity toward acid-catalysed cycloisomerisation investigated.In boiling dichloromethane of 1,2-dibromoethane in the presence of a catalytic amount of methanesulfonic acid, 1,1,
- Marcuzzi, Franco,Azzena, Ugo,Melloni, Giovanni
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p. 2957 - 2960
(2007/10/02)
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- PALLADIUM-MEDIATED REACTION BETWEEN ARYL IODIDES AND STEREODEFINED 2-ARYLETHENYLDIMETHYLPHENYLSILANES OR 2-ARYLETHYNYLDIMETHYLPHENYLSILANES, IN THE PRESENCE OF A FLUORIDE ION SOURCE
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Stereodefined 2-arylethenyldimethylphenylsilanes, 1, do react with aryl iodides, 6, containing an electron-donating substituent as well as with 2-thienyl iodide, 7, in the presence of a catalytic amount of a palladium complex and a molar excess of a 1 M T
- Rossi, Renzo,Carpita, Adriano,Messeri, Tommaso
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- REACTIONS OF ORGANOMETALLIC COMPOUNDS CATALYZED BY TRANSITION METAL COMPLEXES. XIV. SELECTION OF REAGENTS IN THE REACTIONS OF ORGANOMETALLIC COMPOUNDS WITH ORGANIC HALIDES CATALYZED BY PALLADIUM COMPLEXES
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The effect of the nature of the organic groups in organometallic compounds RM and organic halides R'X (R,R' = Ph, p-MeOC6H4, PhCC, C3H7, Allyl; X = Br, I) on the selectivity and duration of the cross-coupling reactions in the presence of palladium complexes was studied.It was shown that the yield of the cross-coupling product depends not only on the nature of R and R' but also on which of the organic groups is in the organometallic compund and which is in the organic halide.The paths leading to the formation of the homocoupling products in the reactions of organometallic compounds with organic halides through entry of the Pd(0) complex at the C-M bond in the organometallic compound and also as a result of exchange of the organic groups between the R'PdXL2 and RM are discussed.
- Bumagin, N. A.,Ponomarev, A. B.,Beletskaya, I. P.
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p. 1222 - 1231
(2007/10/02)
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- PALLADIUM CATALYZED C-C COUPLING FOR SYNTHESIS OF pi -CONJUGATED POLYMERS COMPOSED OF ARYLENE AND ETHYNYLENE UNITS.
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Palladium compounds such as Pd(PPh//3)//4 and Pd(OAc)//2 catalyze polycondensation between dihalo aromatic compounds, X-Ar-X (Ar equals p-phenylene, 2,5-thiophenediyl, 9,10-anthracenediyl, 2,6-pyridinediyl, p-benzene-dicarbonyl, p-xylene- alpha , alpha prime -diyl), and acetylenic compounds (p-C//6H//4(C EQUVLNT CH)//2 or p-C//6H//4(C EQUVLNT CMgBr)//2). The polymers obtained have high thermal stabilities and most of them show fluorescence. One of the polymers is converted into semiconductors by doping with electron acceptors.
- Sanechika,Yamamoto,Yammoto
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p. 752 - 755
(2007/10/02)
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- Synthesis of cedranoid sesquiterpenes. II. Functionalization at carbon 121
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Dimethyl 6,6-dimethyl-7-oxotricyclo2,8>octane-1,8-dicarboxylate (6) undergoes homoconjugate addition wit lithium diphenylcuprate to give dimethyl 3-hydroxy-4,4-dimethyl-exo-8-phenyl-cis-bicyclooct-2-ene-1,2-dicarboxylate (12a), w
- Yates, Peter,Stevens, Kenneth E.
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p. 825 - 834
(2007/10/02)
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- Thermochemical Bond Dissociation Energies of Carbon-Magnesium Bonds
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The heats of formation of 29 alkylmagnesium bromides, isobutyl bromide, and neopentyl bromide have been determined, and bond dissociation energies have been derived for the Grignard reagents.For saturated alkyl derivatives the C-Mg bond strength decreases with an increasing number of β-hydrogens in the series methyl, neopentyl, isobutyl, butyl, ethyl, 1-ethylpropyl, 1-methylpropyl, isopropyl, and t-butyl.Bonding in alkyl bromides and alkylmagnesium bromides is discussed.
- Holm, Torkil
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p. 464 - 467
(2007/10/02)
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