1005-64-7Relevant academic research and scientific papers
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.
Nitrogen-Doped Carbon-Encapsulated Nickel/Cobalt Nanoparticle Catalysts for Olefin Migration in Allylarenes
Kramer, S?ren,Mielby, Jerrik,Buss, Kasper,Kasama, Takeshi,Kegn?s, S?ren
, p. 2930 - 2934 (2017)
Olefin migration in allylarenes is typically performed with precious-metal-based homogeneous catalysts. In contrast, very limited progress has been made with the use of cheap, Earth-abundant base metals as heterogeneous catalysts for these transformations—in spite of the obvious economic and environmental advantages. Herein, we report on the use of an easily prepared heterogeneous catalyst material for the migration of olefins, in particular, for allylarenes. The catalyst material consists of nickel/cobalt alloy nanoparticles encapsulated in nitrogen-doped carbon shells. The encapsulated nanoparticles are stable in air and are easily collected by centrifugation, filtration, or magnetic separation. Furthermore, we demonstrate that the catalysts can be reused several times and provide continuously high yields of the olefin-migration product.
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.
Biocatalytic single-step alkene cleavage from aryl alkenes: An enzymatic equivalent to reductive ozonization
Mang, Harald,Gross, Johannes,Lara, Miguel,Goessler, Christian,Schoemaker, Hans E.,Guebitz, Georg M.,Kroutil, Wolfgang
, p. 5201 - 5203 (2006)
(Chemical Equation Presented) O2 can do: Innocuous molecular oxygen O2 is the only reagent needed to perform highly chemoselective biocatalytic single-step alkene-cleavage reactions (see scheme). The products are analogous to those of (reductive) ozonization and related metal-based methods. In contrast neither special equipment nor an additional reducing agent is required. The biocatalytic reaction can be performed at ambient temperature. Depending on the substrate, aldehydes or ketones are obtained.
Enantioselective copper-catalyzed allylic alkylation with dialkylzincs using phosphoramidite ligands
Malda, Hinke,Van Zijl, Anthoni W.,Arnold, Leggy A.,Feringa, Ben L.
, p. 1169 - 1171 (2001)
Matrix presented In the presence of a catalytic amount of copper salts, cinnamyl halides undergo a regio- and enantioselective SN2′ alkylation with dialkylzincs using chiral phosphoramidites as ligands. An SN2′:SN2 ratio o
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.
An unexpected reaction between 2-aryl-1-nitro-1-alkenes and trialkylgallium compounds
Han, Ying,Huang, Yao-Zeng,Zhou, Cheng-Ming
, p. 3347 - 3350 (1996)
A novel reaction between 2-aryl-1-nitro-1-alkenes and trialkylgallium compound via NO2/alkyl substitution is found, and a possible mechanism is proposed.
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.
Efficient in situ palladium nano catalysis for Z-selective semi transfer hydrogenation of internal alkynes using safer 1, 4-butanediol
Rapeti, Siva Kumar,Kasina, Krishna Chaitanya,Gundepaka, Prasad,Birudaraju, Saritha,Sailaja
, (2020)
Simple and efficient in situ generated palladium nanoparticles (PdNPs) in PEG-4OO catalyzed semi transfer hydrogenation of internal alkynes to Z-alkenes with excellent selectivity along with the formation of beneficial γ-butyrolactone as a byproduct using low quantity of safer and attractive 1, 4-butanediol as a hydrogen source was described.
