1005-64-7Relevant articles and documents
Addition of organocopper reagents to allylic acrylates - The preparation of γ, δ-unsaturated acids and subsequent functionalization to γ-lactones
Eriksson, Magnus,Hjelmencrantz, Anders,Nilsson, Martin,Olsson, Thomas
, p. 12631 - 12644 (1995)
Conjugate addition of monoorganocopper compounds with iodotrimethylsilane (TMSI) or lithium diorganocuprates, with or without halosilanes, to allylic acrylates give allylic silyl ketene acetals/ester enolates. These can undergo Claisen rearrangement to give diastereomeric mixtures of γ, δ-unsaturated acids after aqueous work-up. For organocuprates, the diastereomeric ratio is strongly affected by the halosilane. Either diastereomer can be obtained as major product by proper choice of copper reagent. Cyclization of the acids followed by reduction gives γ-lactones in good yields. A copper iodide/dimethyl sulfide complex is introduced as an excellent precursor to organocopper reagents.
Development of a One-Pot tandem reaction combining ruthenium-catalyzed alkene metathesis and enantioselective enzymatic oxidation to produce Aryl epoxides
Denard, Carl A.,Bartlett, Mark J.,Wang, Yajie,Lu, Lu,Hartwig, John F.,Zhao, Huimin
, p. 3817 - 3822 (2015)
We report the development of a tandem chemoenzymatic transformation that combines alkene metathesis with enzymatic epoxidation to provide aryl epoxides. The development of this one-pot reaction required substantial protein and reaction engineering to improve both selectivity and catalytic activity. Ultimately, this reaction converts a mixture of alkenes into a single epoxide product in high enantioselectivity and moderate yields and illustrates both the challenges and benefits of tandem catalysis combining organometallic and enzymatic systems.
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Grummitt,Christoph
, (1951)
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Synthesis of mono-, di-, and trisilyl-substituted alkenes via the hydrosilylation of methylenecyclopropanes catalyzed by Rh(I) complexes
Bessmertnykh,Blinov,Grishin,Donskaya,Tveritinova,Yur'eva,Beletskaya
, p. 6069 - 6076 (1997)
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Stereoselective Chromium-Catalyzed Semi-Hydrogenation of Alkynes
Gregori, Bernhard J.,Nowakowski, Michal,Schoch, Anke,P?llath, Simon,Zweck, Josef,Bauer, Matthias,Jacobi von Wangelin, Axel
, p. 5359 - 5363 (2020)
Chromium complexes have found very little applications as hydrogenation catalysts. Here, we report a Cr-catalyzed semi-hydrogenation of internal alkynes to the corresponding Z-alkenes with good stereocontrol (up to 99/1 for dialkyl alkynes). The catalyst comprises the commercial reagents chromium(III) acetylacetonate, Cr(acac)3, and diisobutylaluminium hydride, DIBAL?H, in THF. The semi-hydrogenation operates at mild conditions (1-5 bar H2, 30 °C).
Effects of Phenyl and Alkyl Substitutions on the Hydrogenation of Allene with Diimide
Okuyama, Tadashi,Toyoshima, Kenzo,Fueno, Takayuki
, p. 1604 - 1608 (1980)
Hydrogenation of phenylpropadiene, 3-phenyl-1,2-butadiene, 1-phenyl-1,2-butadiene, and 1-phenyl-1,2-pentadiene with diimide (HN=NH) in refluxing methanol was conducted.The product distribution was analyzed as a function of reaction time, and the selectivities of the addition as well as relative reactivities were determined.Adverse steric effects of the phenyl group at the terminus of one double bond against "cis-coplanar" attack of diimide on the other double bond were found to be remarkably large.Alkyl groups activated the remote double bond of alkylallenes noticeably.This apparent electronic effect was theoretically rationalized from ab initio STO-3G model calculations of the chemical interactions.
Reaction of indium ate complexes with allylic compounds. Controlling S N2/SN2′ selectivity by solvents
Hirashita, Tsunehisa,Hayashi, Yousuke,Mitsui, Kazuma,Araki, Shuki
, p. 3225 - 3228 (2004)
Vinyl and methylindium ate complexes (indates) were prepared and both the tendency of immigration and regioselectivity toward cinnamyl bromide were investigated. The vinyl group was more preferably transferred than the Me group, giving a regioisomeric mixture of SN2 and SN2′ products. The ratio of SN2/SN2′ selectivity can be controlled by solvents; in the presence of polar solvents, such as N-butylpyrrolidone (NBP) and THF, the SN2′ product was mainly obtained, whereas the SN2 product was selectively prepared in solutions containing hexane. The vinylindium compound, generated by the reaction of allylic-type diindium reagents with imine, was also converted to the corresponding vinyl indate, which was allowed to react with allyl chloride to give a three-component coupling product.
REDUCTION BY A MODEL OF NAD(P)H. 44. TRANSITION METAL CATALYZED REDUCTION OF ALLYLIC ACETATE
Nakamura, Kaoru,Ohno, Atsuyoshi,Oka, Shinzaburo
, p. 3335 - 3336 (1983)
Allylic acetates were reduced regioselectively to alkenes by a model of NAD(P)H via catalytic activation with transition metal complexes.
Pair-Selective Coupling of Alkynes with Alkenes on Zirconocene Complex
Takahashi, Tamotsu,Xi, Zhenfeng,Rousset, Christophe J.,Suzuki, Noriyuki
, p. 1001 - 1004 (1993)
When ethylene and alkynes such as 4-octyne and diphenylacetylene were treated with Cp2ZrBu2, highly pair selective coupling products were formed in high yields.Similarly, styrene or trimethylvinylsilane also afforded cross coupling products with alkynes on zirconocene complex.
Csicsery
, p. 336,341 (1967)
In situ 1H-PHIP-NMR studies of the stereoselective hydrogenation of alkynes to (E)-alkenes catalyzed by a homogeneous [Cp*Ru]+ catalyst
Schleyer,Niessen,Bargon
, p. 423 - 426 (2001)
The hydrogenation of internal alkynes using a [Cp*Ru(alkene)]+ complex leads to the formation of (E)-alkenes. This ruthenium complex represents one of the few homogeneous catalysts that trans-hydrogenate internal alkynes directly and stereoselectively. We have studied its stereoselectivity by in situ PHIP-NMR spectroscopy (PHIP = para-hydrogen induced polarization). With this method the initially formed products can be identified and characterized even at very low concentrations and low conversions. Furthermore, their subsequent fate can be evaluated with high sensitivity and with time resolution. Different alkyne substrates were used to demonstrate the universal applicability of this catalyst. The catalyst is not active in combination with terminal alkynes, however, possibly due to the formation of a rather stable vinylidene complex. A mechanism proceeding via a binuclear complex is proposed to explain the formation of the (E)-alkenes.
Development of unique dianionic Ir(III) CCC pincer complexes with a favourable spirocyclic NHC framework
Yan, Zhi-Bo,Dai, Kun-Long,Yang, Bin-Miao,Li, Zi-Hao,Tu, Yong-Qiang,Zhang, Fu-Min,Zhang, Xiao-Ming,Peng, Meng,Chen, Qi-Long,Jing, Ze-Ran
, p. 1761 - 1766 (2020)
A new type of dianionic Ir(III) CCC pincer complexes (SNHC-Ir, 1a-1c) is successfully designed and synthesized by developing a one-step methodology, which involves an initial coordination of Ir(I) with the NHC and subsequent metallation of double sp2C- H bonds. This method is considerably useful over those reported by using strong coordination ligand or carbonic anion exchange, and would provide an alternative efficient template of organometallics synthesis. Experimental and density functional theory (DFT) calculation results indicate that the spirocyclic framework is a favourable factor for the facile formation and stabilization of these complexes. Primary investigation shows that chloride 1b can well catalyze homo and hetero addition of styrene derivatives and remote olefin isomerization, which represents the first catalytic application of the dianionic CCC pincer complexes.
Photoinduced metalation of nonactivated C-Cl bonds with samarium diiodide: Synthesis of alkenes with high (Z)-selectivity through β-elimination reactions
Concellon, Jose M.,Rodriguez-Solla, Humberto,Simal, Carmen,Huerta, Monica
, p. 5833 - 5835 (2005)
(Chemical Equation Presented) The photoinduced metalation of nonactivated C-Cl bonds of O-acetyl chlorohydrins is promoted by samarium diiodide. As a result of this, β-elimination of O-acetyl chlorohydrins is achieved, affording the corresponding (Z)-alkenes with total or high stereoselectivity.
Alkylation of Allylic Derivatives. 5. Loss of Double-Bond Configuration Associated with α-Alkylation of Allylic Carboxylates with Dialkylcuprates
Goering, Harlan L.,Kantner, Steven S.
, p. 721 - 724 (1983)
Alkylation of cis- and trans-cinnamyl acetate with LiCuMe2 gives primarily the conjugated α-alkylation product, 1-phenyl-1-butene.Detectable loss of double-bond configuration is observed with the trans-acetate and substantial loss of configuration is observed with the cis-acetate.The partial loss of double-bond configuration in the α-alkylation product has profound mechanistic implications, which are discussed.
Preparation of Organophilic Pd-Montmorillonite, An Efficient Catalyst in Alkyne Semihydrogenation
Mastalir, A.,Kiraly,Szoellosi, Gy.,Bartok
, p. 146 - 152 (2000)
Palladium particles incorporated into organophilic montmorillonite (Pd-M) were prepared via a novel synthetic method, mediated by a cationic surfactant stabilizer. The materials were characterized by UV-Vis, ICP-AES, and TEM. Two representative samples (Pd-M1 and Pd-M2), with metal contents of 0.1% and 0.46%, respectively, were investigated in detail. TEM measurements indicated that the diameters of the Pd particles observed were in the range 1.5-6 nm. It is suggested that most of the Pd particles are situated on the external surface of the clay lamellae. Both Pd-M samples exhibited marked catalytic activities and stereoselectivities in the liquid-phase hydrogenation of 1-phenyl-1-butyne. For the production of the cis-alkene stereoisomer, Pd-M2 proved to be less active but more stereoselective than Pd-M1. The stereoselectivities obtained for Pd-M2 in n-hexane (86-88%) were nearly as high as those experienced for the Lindlar catalyst.
Temperature and Matrix Effects on Migratory Aptitude and Stereochemistry in 1,2-Migration to a Divalent Carbon
Tomioka, Hideo,Ueda, Hiroaki,Kondo, Shingo,Izawa, Yasuji
, p. 7817 - 7818 (1980)
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Organic reactions involving transition metals III. The palladium(II)-catalysed dimerization of olefinic compounds
Barlow,Bryant,Haszeldine,Mackie
, p. 215 - 226 (1970)
The palladium(II)-catalysed dimerization of olefins has been investigated. The olefinic compounds, ethylene, propene, n-butenes, methyl acrylat, and styrene, have been successfully dimerized, and the pairs of olefinic compounds, ethylene and propene, propene and 1-butene, ethylene and cyclopentene, ethylene and methyl acrylate, ethylene and styrene, and methyl acrylate and styrene successfully codimerized, using dichlorobis(benzonitrile)palladium or palladium dichloride as catalyst. In all cases, high proportions of straight-chain dimers are formed, and olefin-isomerization is a closely associated feature of the reaction. A mechanism involving a hydridopalladium(II) compound as the catalytically active species is suggested.
Novel synthesis of alkenes via triethylborane-induced free-radical reactions of alkyl iodides and β-nitrostyrenes
Liu,Jang,Shih,Hu,Chu,Yao
, p. 6021 - 6028 (2001)
Reactions of (E)-β-nitrostyrenes 1 and triethylborane 2 or tricyclohexylborane 4 in THF solution at room temperature in the presence of oxygen in the air as radical initiator generate high yields of trans-alkenes (E)-3 or (E)-5. Medium to high yields of d
Copper-catalyzed regioselective allylic substitution reactions with indium organometallics
Rodriguez, David,Sestelo, Jose Perez,Sarandeses, Luis A.
, p. 2518 - 2520 (2003)
The first nucleophilic allylic substitution reactions of triorganoindium compounds with allylic halides and phosphates are reported. The reactions of trialkyl- and triarylindium reagents with cinnamyl and geranyl halides and phosphates, with the aid of co
Polylithiumorganic compounds -19. Regioselective carbon-carbon σ-bond scission followed by a 1,6-proton shift upon the reductive metalation of benzylidenecyclopropane derivatives with lithium metal
Maercker, Adalbert,Daub, Volker E. E.
, p. 2439 - 2458 (1994)
Depending on the substituent α-substituted benzylidenecyclopropanes (32) react more or less readily with lithium dust (2% sodium) in diethyl ether whereby a regioselective scission of only the cyclopropane σ-bond cis to the phenyl ring takes place. Upon raising the temperature the primarily formed 1,3-dilithiumorganic compound due to an agostic interaction rearranges by a 1,6-proton shift into a doubly bridged 1,4-dilithio compound. With α-methylbenzylidenecyclopropane (32c) this rearrangement was shown to occur intermolecularly via a trilithiumorganic compound 56. The suggested mechanism of these reductive metalation reactions via a bisected radical anion 87 where the lithium is mainly bound to the cyclopropyl carbon atom and oriented syn to the phenyl ring, was supported by MNDO (geometries) and ab initio (energies) calculations.
Catalytic Hydrogenation of Alkenes and Alkynes by a Cobalt Pincer Complex: Evidence of Roles for Both Co(I) and Co(II)
Alawisi, Hussah,Arman, Hadi D.,Tonzetich, Zachary J.
, p. 1062 - 1070 (2021)
The Co(I) complex, [Co(N2)(CyPNP)] (CyPNP = anion of 2,5-bis-(dicyclohexylphosphinomethyl)pyrrole), is active toward the catalytic hydrogenation of terminal alkenes and the semi-hydrogenation of internal alkynes under 2 bar of H2 (g) at room temperature. The products of alkyne semi-hydrogenation are a mixture of E- and Z-alkenes. By contrast, use of the related cobalt(I) precatalyst, [Co(PMe3)(CyPNP)], results in formation of exclusively Z-alkenes. A semi-stable Co(II) species, [CoH(CyPNP)], can also be generated by treatment of degassed solutions of [Co(N2)(CyPNP)] with H2. The CoII-hydride displays activity toward both alkene hydrogenation and isomerization, but its instability hampers implementation as a catalyst. Several species relevant to potential catalytic intermediates have been isolated and detected in solution. These compounds include alkene and alkyne adducts of Co(I) as well as a Co(III) dihydride species. Catalytic results with the compounds examined are most consistent with a process involving shuttling between Co(I) and Co(III) states. However, generation of small quantities of Co(II) during catalytic turnover appears to be responsible for the isomerization observed for alkyne semi-hydrogenation. The interplay of cobalt oxidation states within the same catalyst system is discussed in the context of mechanistic scenarios for catalytic hydrogenation.
Free-Radical Reactions of Trialkylboranes with β-Nitrostyrenes to Generate Alkenes
Yao, Ching-Fa,Chu, Cheng-Ming,Liu, Ju-Tsung
, p. 719 - 722 (1998)
β-Nitrostyrenes 1 react with trialkylboranes under a nitrogen atmosphere to generate high yields of alkenes 2. The mechanism is proposed to be a free-radical reaction via NO2/alkyl substitution since the reaction is stimulated by the presence of a trace of oxygen in the nitrogen or tert-butyl peroxide or by photolysis and is retarded or inhibited by the addition of galvinoxyl to the solution.
Regiocontrolled Reductive Vinylation of Aliphatic 1,3-Dienes with Vinyl Triflates by Nickel Catalysis
Pang, Xiaobo,Zhao, Zhen-Zhen,Wei, Xiao-Xue,Qi, Liangliang,Xu, Guang-Li,Duan, Jicheng,Liu, Xue-Yuan,Shu, Xing-Zhong
, p. 4536 - 4542 (2021)
The regiocontrolled functionalization of 1,3-dienes has become a powerful tool for divergent synthesis, yet it remains a long-standing challenge for aliphatic substrates. Herein, we report a reductive approach for a branch-selective 1,2-hydrovinylation of aliphatic 1,3-dienes with R-X electrophiles, which represents a new selectivity pattern for diene functionalization. Simple butadiene, aromatic 1,3-dienes, and highly conjugated polyene were also tolerated. The combination of Ni(0) and the phosphine-nitrile ligand generally resulted in >20:1 regioselectivity with the retention of the geometry of the C3-C4 double bonds. This reaction proceeds with a broad substrate scope, and it allows for the conjugation of two biologically active units to form more complex polyene molecules, such as tetraene and pentaene as well as heptaene.
Bergelson et al.
, p. 2709 (1967)
Desulfurization of benzylic mercaptans by triiron dodecacarbonyl under acidic and biphasic conditions
Alper, Howard,Sibtain, Fazle
, p. 225 - 229 (1985)
The biphasic reaction of benzylic mercaptans with triiron dodecacarbonyl, 48-50% tetrafluoroboric acid, and benzene affords desulfurized products in good to excellent yields. This reaction is superior to that effected in the presence of sodium dodecylbenzenesulfonate, a phase transfer agent for acidic processes.
E-Selective Manganese-Catalyzed Semihydrogenation of Alkynes with H2 Directly Employed or In Situ-Generated
Ammaturo, Antonio,Csendes, Zita,Farrar-Tobar, Ronald A.,Fleissner, Sarah,Hoffmann, Helmuth,Kirchner, Karl,Veiros, Luis F.,Weber, Stefan
, p. 2253 - 2260 (2022/02/14)
Selective semihydrogenation of alkynes with the Mn(I) alkyl catalyst fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (dippe = 1,2-bis(di-iso-propylphosphino)ethane) as a precatalyst is described. The required hydrogen gas is ei
Kinetic resolution ofN-aryl β-amino alcoholsviaasymmetric aminations of anilines
Guo, Zheng,Xie, Jinglei,Hu, Tao,Chen, Yunrong,Tao, Houchao,Yang, Xiaoyu
supporting information, p. 9394 - 9397 (2021/09/22)
An efficient kinetic resolution ofN-aryl β-amino alcohols has been developedviaasymmetricpara-aminations of anilines with azodicarboxylates enabled by chiral phosphoric acid catalysis. Broad substrate scope and high kinetic resolution performances were afforded with this method. Control experiments supported the critical roles of the NH and OH group in these reactions.
