135-98-8Relevant academic research and scientific papers
Alkylation of benzene with ethylene on nickel-containing amorphous and crystalline aluminosilicates
Minachev,Isakov,Kalinin,Lapidus,Eidus
, p. 1255 - 1259 (1974)
1. The zeolite-containing catalysts ABFZ-3 and ABFZ-6 have a high activity in the alkylation of benzene with ethylene. 2. Amorphous and crystalline aluminosilicates that contain Ni (as Ni2+ and NiO) are polyfunctional catalysts for the alkylation of benzene with ethylene, and can direct the reaction toward the formation of predominantly sec-butylbenzene and ethylbenzene, or sec-butylbenzene and butenes.
Chiral organolanthanides designed for asymmetric catalysis. A kinetic and mechanistic study of enantioselective olefin hydroamination/cyclization and hydrogenation by C1-Symmetric Me2Si(Me4C5)(C5H 3R*)Ln complexes where R* = chiral auxiliary
Giardello, Michael A.,Conticello, Vincent P.,Brard, Laurent,Gagné, Michel R.,Marks, Tobin J.
, p. 10241 - 10254 (1994)
The C1-symmetric organolanthanide complexes Me2SiCp″(R*Cp)LnE(SiMe3)2 (Cp″ = η5-Me4C5; R* = (1S,2S,5R)-trans-5-methyl-cis-2-(2-propyl)cyclohexyl ((+)-neomenthyl), (1R,2S,5R)-cis-5-methyl-trans-2-(2-propyl)-cyclohexyl ((-)-menthyl), and (1R,2S,5R)-cis-5-methyl-trans-2-(2-phenyl-2-propyl)-cyclohexyl((-)- phenylmenthyl); Ln = La, Nd, Sm, Y, Lu; E = N, CH) serve as precatalysts for the efficient regio- and enantioselective hydroamination/ cyclization of the amino olefins 1-aminopent-4-ene, 2-amino-hex-5-ene, 2,2-dimethyl-1-aminopent-5-ene, and 2,2-dimethyl-1-aminohex-5-ene to yield the corresponding heterocycles 2-methylpyrrolidine, 2,5-dimethylpyrrolidine, 2,4,4-trimethylpyrrolidine, and 2,5,5-trimethylpiperidine, respectively. At 25 °C, enantiomeric excesses as high as 69% (74% at -30 °C) and turnover frequencies as high as 93 h-1 are observed. Catalyst epimerization is observed in the presence of primary amines; however, equilibrium homochiralities are frequently very high (in some cases >95%), and epimerization is complete in the early stages of preparative scale reactions. The (+)-neomenthyl, (-)-menthyl, and (-)-phenylmenthyl catalysts afford 2-methylpyrrolidines with the (R) catalyst configuration selecting for (R) product configuration and (S) catalyst configuration selecting for (S) product configuration. Product stereochemistry can be understood in terms of olefin insertion via a chairlike, seven-membered transition state. The (+)-neomenthyl precatalysts (Ln = Nd, Sm) effect the cyclization of 2-aminohex-5-ene to trarns-2,5-dimethylpyrrolidine in >95% diastereoselectivity at 25 °C. The corresponding hydrocarbyl complexes serve as precatalysts for the efficient asymmetric deuteration and hydrogenation of styrene and 2-phenyl-1-butene, respectively. For the organosamarium-derived catalysts, 2-phenyl-1-butene hydrogenation to yield exclusively 2-phenylbutane-1,2-d2 under D2 in a non-mass-transfer-limited reaction regime obeys the rate law v = k[olefin]0[lanthanide]1/2[H2]1, suggesting rapid, operationally irreversible olefin insertion (the step in which stereochemistry is fixed), a rapid preequilibrium involving an alkyl or alkyl/hydride dimer, and turnoverlimiting hydrogenolysis of an intermediate samarium alkyl with kH2/kD2 = 1.5-2.3 at 25 °C. Enantiomeric excesses as high as 64% (96% at -80 °C) and turnover frequencies as high as 26 000 h-1 are observed at 25 °C, PH2 = 1 atm for the hydrogenation of 2-phenyl-1-butene. The (R) catalyst configuration selects for the (R) product and the (S) catalyst configuration for the (S) product, with no major nonlinear effects evident in studies with (R) + (S) mixtures. Product stereochemistry can be understood in terms of olefin approach along the ring centroid-metal-ring centroid angle bisector. Under the same conditions, the deuteration of styrene proceeds at comparable rates and higher selectivities, 72% (S) and 43% (R) ee with the (70/30) (S)/(R) and (R)-(-)-menthyl samarium hydrocarbyls, respectively. Exclusive formation of ethylbenzene-1,2-d2 under D2 indicates that β-hydride elimination/readdition does not effectively compete with turnover-limiting deuterolysis.
Alkyl Metal Asymmetric Reduction. 12. Optically Active Phenylalkanes from Organoaluminum Derivatives and Aliphatic Ketones
Giacomelli, Giampaolo,Lardicci, Luciano
, p. 4335 - 4337 (1982)
The reaction of β-branched alkylaluminum dichloride with some aliphatic ketones has been studied in various solvents at room temperature.In benzene, the organoaluminum derivative rapidly reduces the ketone with formation of the alkoxyaluminum dichloride, which slowly alkylates the benzene to the corresponding phenylalkane.When optically active (2-methylbutyl)aluminum dichloride is used, both the carbinol from hydrolysis of the alkoxy aluminum species and the phenylalkane are optically active and of opposite absolute configuration.The overall results are also interpreted on the basis of previous findings, and a mechanism that accounts f or the formation of the optically active phenylalkanes is presented.
Stereochemistry of Friedel-Crafts Alkylation of Benzene with Optically Active 2-Chlorobutane
Suga, Sohei,Segi, Masahito,Kitano, Kiyoyuki,Masuda, Shinji,Nakajima, Tadashi
, p. 3611 - 3612 (1981)
The alkylation of benzene with (+)-2-chlorobutane (1) by Lewis acid catalyst gave stereospecifically (-)-2-phenylbutane (2) with inversion of configuration at low temperature for short reaction time.A lowering of the stereospecificity of the reaction was found to be partly due to the racemization of (+)-1- and (-)-2.
Synthesis of iron(III) complex bearing tridentate β-Aminoketonato Ligand: Application to iron-catalyzed cross-coupling reaction of arylmagnesium bromides with alkyl halides
Yamaguchi, Yoshitaka,Ando, Hiroaki,Nagaya, Makoto,Hinago, Hideto,Ito, Takashi,Asami, Masatoshi
, p. 983 - 985 (2011)
A tridentate β-aminoketonato iron complex was prepared by the reaction of lithium β-aminoketonato with FeCl3. This iron complex was found to be an efficient catalyst for the crosscoupling reaction between arylmagnesium bromides and alkyl halides.
Enantioselective hydrogenations of arylalkenes mediated by [Ir(cod)(JM-phos)]+ complexes
Hou, Duen-Ren,Reibenspies, Joseph,Colacot, Thomas J.,Burgess, Kevin
, p. 5391 - 5400 (2001)
Phosphine oxazoline ligands 1a-j were converted to the corresponding [Ir(cod)(phosphine oxazoline)]+ complexes 2a-j. X-ray diffraction analyses of complexes 2b, 2h, 2i, and 2j were performed. The tert-butyl-, 1,1-diphenylethyl-, and phenyl-oxazoline complexes (2b, 2h, and 2i, respectively) had typical square planar metal environments with chair-like metallocyclic rings. However, the 3,5-di-tert-butylphenyl oxazoline complex 2j was distorted toward a tetrahedral metal geometry. This library of complexes was tested in asymmetric hydrogenations of several arylalkenes. High enantioselectivities and conversions were observed for some substrates. A possible special role for the HPh2C-oxazoline substituent in asymmetric hydrogenations was identified and is discussed. In attempts to rationalize why high enantioselectivities were not observed for some alkenes, a series of deuterium labeling experiments were performed to probe for competing reactions that occurred prior to the hydrogenation step. Double bond migrations were inferred for several substrates, and this is a significant complication in asymmetric hydrogenations of arylalkenes that had not been discussed prior to this study. A mechanistic rationale is proposed involving competing double bond migration for some but not all substrates. Appreciation of this complication will be valuable in further studies aimed at optimization of enantioselection in asymmetric hydrogenations of unfunctionalized alkenes. Wiley-VCH Verlag GmbH, 2001.
Comparison of Lewis Acids as Catalyst for the Alkylation of Benzene with s-Butyl Chloride
Segi, Masahito,Nakajima, Tadashi,Suga, Sohei
, p. 1465 - 1466 (1980)
The Friedel-Crafts alkylation of benzene with s-butyl chloride has been carried out in the presence of various Lewis acid catalysts.The relative order of catalyst activity is AlBr3, AlCl3, MoCl5, SbCl5 > TaCl5 > NbCl5 > FeCl3 > ZrCl4 > TiCl4 >> WCl6.The effect of addition of nitromethane on alkylation has been investigated.
Iron-Catalyzed Cross-Coupling of Primary and Secondary Alkyl Halides with Aryl Grignard Reagents
Nakamura, Masaharu,Matsuo, Keiko,Ito, Shingo,Nakamura, Eiichi
, p. 3686 - 3687 (2004)
An iron-catalyzed cross-coupling reaction of a primary or secondary alkyl halide with an aryl Grignard reagent proceeds under mild conditions to give the corresponding coupling product in quantitative yield. Copyright
Probing the mechanisms of enantioselective hydrogenation of simple olefins with chiral rhodium catalysts in the presence of anions
Buriak, Julian M.,Klein, Jason C.,Herrington, Deborah G.,Osborn, John A.
, p. 139 - 150 (2000)
The strong influence of various anions upon the hydrogenation of 2-phenyl-1-butene, catalyzed by chiral rhodium catalysts was investigated. Both sulfonates and halides exert large increases in the enantioselectivity when [Rh{(-)-bdpp}(NBD)]ClO4 (bdpp = 2,4-bis(diphenylphosphino)pentane, NBD=2,5-norbornadiene) is used as the catalyst precursor at high pressures (70 atm) of dihydrogen in nonpolar solvents. A dihydride mechanism similar to that for Wilkinson's catalyst [RhCl(PPh3)3] was shown to be operating at both high- and low-pressure conditions through a combination of catalytic studies, 31P, 1H and parahydrogen-induced polarization (PHIP) NMR experiments. With sulfonate and in neat methanol, however, a mechanistic switch takes place from a dihydride route (dihydrogen addition before olefin binding) at high pressure to an unsaturate route (olefin binding before dihydrogen addition) at low pressures (30 atm). Olefin isomerization is inhibited by halide addition, but occurs with sulfonate and in neat methanol through what is most likely a π-allyl mechanism. A detailed understanding of the effects of addition of these anions is crucial for development of new classes of catalysts capable of efficient enantioselective reduction of prochiral olefins lacking a secondary polar binding group.
Photoinduced Decomposition of Peracetic Acid in Isopropylbenzene
Ogata, Yoshiro,Tomizawa, Kohtaro
, p. 2419 - 2420 (1980)
Irradiation of peracetic acid in isopropylbenzene with 254 nm and over 290 nm lights gave as aromatic products mainly t-butylbenzene, 2-phenyl-2-propanol, and 2,3-dimethyl-2,3-diphenylbutane.The yield of t-butylbenzene was higher in 254 nm photolysis than that with >290 nm, while the yield of hydroxylated aromatics, i. e., 2-phenyl-2-propanol, was much higher with >290 nm than that with 254 nm.The distribution of products was little affected by the intensity of light.These results are discussed by a mechanism involving radicals of different reactivity derived from peracetic acid decomposition.
