19398-86-8Relevant academic research and scientific papers
Anti-Markovnikov Hydroheteroarylation of Unactivated Alkenes with Indoles, Pyrroles, Benzofurans, and Furans Catalyzed by a Nickel-N-Heterocyclic Carbene System
Schramm, York,Takeuchi, Makoto,Semba, Kazuhiko,Nakao, Yoshiaki,Hartwig, John F.
supporting information, p. 12215 - 12218 (2015/10/12)
We report the catalytic addition of C-H bonds at the C2 position of heteroarenes, including pyrroles, indoles, benzofurans, and furans, to unactivated terminal and internal alkenes. The reaction is catalyzed by a combination of Ni(COD)2 and a sterically hindered, electron-rich N-heterocyclic carbene ligand or its analogous Ni(NHC)(arene) complex. The reaction is highly selective for anti-Markovnikov addition to α-olefins, as well as for the formation of linear alkylheteroarenes from internal alkenes. The reaction occurs with substrates containing ketones, esters, amides, boronate esters, silyl ethers, sulfonamides, acetals, and free amines.
Selective semihydrogenation of alkynes on shape-controlled palladium nanocrystals
Chung, Jooyoung,Kim, Chanhoi,Jeong, Hansaem,Yu, Taekyung,Binh, Do Huy,Jang, Jyongsik,Lee, Jaichan,Kim, B. Moon,Lim, Byungkwon
, p. 919 - 925 (2013/08/25)
A systematic study on the selective semihydrogenation of alkynes to alkenes on shape-controlled palladium (Pd) nanocrystals was performed. Pd nanocrystals with a cubic shape and thus exposed {100} facets were synthesized in an aqueous solution through the reduction of Na2PdCl4 with L-ascorbic acid in the presence of bromide ions. The Pd nanocubes were tested as catalysts for the semihydrogenation of various alkynes such as 5-decyne, 2-butyne-1,4-diol, and phenylacetylene. For all substrates, the Pd nanocubes exhibited higher alkene selectivity (>90 %) than a commercial Pd/C catalyst (75-90 %), which was attributed to a large adsorption energy of the carbon-carbon triple bond on the {100} facets of the Pd nanocubes. Our approach based on the shape control of Pd nanocrystals offers a simple and effective route to the development of a highly selective catalyst for alkyne semihydrogenation. Catalysis3: The semihydrogenation of various alkynes by Pd nanocubes was investigated. The nanocubes exhibited high alkene selectivity and complete cis-selectivity, thus surpassing the Lindlar catalyst. The shape control of Pd nanocrystals provides a simple and efficient way for generating highly selective catalysts for the semihydrogenation of alkynes.
Stabilization of long-chain intermediates in solution. octyl radicals and cations
Teodorovi?, Aleksandar V.,Badjuk, Dalibor M.,Stevanovi?, Nenad,Pavlovi?, Radoslav Z.
, p. 19 - 24 (2013/06/26)
The rearrangements of 1-octyl, 1-decyl and 1-tridecyl intermediates obtained from thermal lead(IV) acetate (LTA) decarboxylation of nonanoic, undecanoic and tetradecanoic acid were investigated experimentally through analysis and distribution of the products. The relationships between 1,5-, 1,6- and possibly existing 1,7-homolytic hydrogen transfer in 1-octyl-radical, as well as successive 1,2-hydride shift in corresponding cation have been computed via Monte-Carlo method. Taking into account that ratios of 1,5-/1,6-homolytic rearrangements in 1-octyl- and 1-tridecyl radical are approximately the same, the simulation shows very low involvement of 1,7-hydrogen rearrangement (1,5-/1,6-/1,7-hydrogen rearrangement = 85:31:1) in 1-octyl radical.
A selective Ru-catalyzed semireduction of alkynes to Z olefins under transfer-hydrogenation conditions
Belger, Christian,Neisius, N. Matthias,Plietker, Bernd
supporting information; experimental part, p. 12214 - 12220 (2011/03/17)
By using a readily available, air- and moisture-stable dihydrido-Ru complex, a variety of Z olefins are accessible under transfer-hydrogenation conditions with formic acid as the hydrogen source in excellent yields and Z/E selectivities. A discerning transformation: Z-Configured C=C bonds are stereoselectively formed from alkynes in the presence of a Ru catalyst with formic acid as the sole H2 source at room temperature (see scheme). A variety of functional groups are compatible with this novel procedure. Operational simplicity and the lack of overreduction products are characteristics for this unprecedented process.
TRANSITION METAL COMPLEXES
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Page/Page column 90-93, (2008/06/13)
A transition metal complex which is a bis-arylimine pyridine MXn complex, comprising a bis-arylimine pyridine ligand having the formula (I), wherein R1-R5, R7-R9, R12 and R14 are each, independently, hydrogen, optionally substituted hydrocarbyl, an inert functional group, or any two of R1-R3 and R7-R9 vicinal to one another taken together may form a ring, and R6 is hydrogen, optionally substituted hydrocarbyl, an inert functional group, or taken together with R7 or R4 to form a ring, R10 is hydrogen, optionally substituted hydrocarbyl, an inert functional group, or taken together with R9 or R4 to form a ring, R11 is hydrogen, optionally substituted hydrocarbyl, an inert functional group, or taken together with R12 or R5 to form a ring, R15 is hydrogen, optionally substituted hydrocarbyl, an inert functional group, or taken together with R14 or R5 to form a ring, provided that R13 and at least one of R12 and R14 are independently selected from optionally substituted C1-C30 alkyl, optionally substituted C4-C30 alkyloxy, halogen and optionally substituted C5-C20 aryl, or R13 taken together with R12 or R14 form a ring, or R12 taken together with R11 form a ring and R14 taken together with R15 form a ring, and provided that at least one of R12, R13 and R14 is optionally substituted C4-C30 alkyloxy; M is a transition metal atom in particular selected from Ti, V, Cr, Mn, Fe, Co, Ni, Pd, Rh, Ru, Mo, Nb, Zr, Hf, Ta, W, Re, Os, Ir or Pt; n matches the formal oxidation state of the transition metal atom M; and X is halide, optionally substituted hydrocarbyl, alkoxide, amide, or hydride. The transition metal complexes of the present invention, their complexes with non-coordinating anions and catalyst systems containing such complexes have good solubility in non-polar media and chemically inert non--polar solvents especially aromatic hydrocarbon solvents. The catalyst systems can be used for a wide range of (co-)oligomerization, polymerization and dimerization reactions.
Organic Synthesis with Sulfones n0XXIX Stereospecific hydrogenolysis of vinylic sulfones with grignards and transition metal catalysts (1).
Fabre, J.-L.,Julia, M.
, p. 4311 - 4314 (2007/10/02)
Hydrogenolysis of various vinylic sulfones to the corresponding olefins can be carried out by alkyl Grignard reagents with nickel or palladium catalysts.Yields are good to excellent.Retention of configuration is observed.The influence of ligands is discussed.
Pyrylium-Mediated Conversion of Primary Alkyl Primary Amines into Olefins via Tetrahydrobenzoacridiniums: A Mild Alternative to the Hofmann Elimination
Katritzky, Alan R.,El-Mowafy, Azzahra M.
, p. 3506 - 3511 (2007/10/02)
Primary alkyl primary amines react with the pentacyclic pyrylium 2 to give the corresponding pyridiniums which thermolyze at 150-180 deg C into the olefins in high yield.The terminal olefins are accompanied by cis- and trans-2-olefinic isomers: proportions are elucidated by GLC and advantageously by 13C NMR spectroscopy, combining gated decoupling and (acac)3CrIII.
THE EFFECT OF CROWN ETHER ON STERIC HINDRANCE TO BASE APPROACH IN BIMOLECULAR ELIMINATION: EVIDENCE AGAINST CLUMP AGGREGATE MODEL OF ION-PAIRED ALKOXIDE BASE
Pankova, Magdalena,Zavada, Jiri
, p. 3150 - 3159 (2007/10/02)
The effect of 18-crown-6-ether upon geometrical orientation and rates was investigated in tert-C4H9OK-tert-C4H9OH promoted anti-elimination from two homologous series of tosylates, RCH2CHOTsC5H11 and RCHOTsCH2C5H11 (R = H, CH3, C2H5, n-C3H5, iso-C3H7, tert-C4H9).Steric requirements of the cis- and trans-stereoselective base species operating in the reaction in the absence and in the presence of the crown ether, respectively, have been assessed.An unambiguous distinction has been made between two pending models of the cis-stereoselective (ion-paired) base.
