17397-24-9Relevant academic research and scientific papers
Catalytic tandem oxy-palladation and vinylation
Semmelhack,Epa
, p. 7205 - 7208 (1993)
Intramolecular oxy-palladation of hydroxy-alkenes leads to organo-Pd(II) intermediates which can be trapped by alkenes in chain extension by vinyl substitution; catalysis is efficient using a reoxidation system but the process is limited to substrates which cannot undergo β-hydride elimination from the organo-Pd(II) intermediate.
A MEERWEIN-PONNDORF-VERLEY TYPE REDUCTION OF α,β UNSATURATED KETONES TO ALLYLIC ALCOHOLS CATALYZED BY MgO
Kaspar, J.,Trovarelli, A.,Lenarda, M.,Graziani, M.
, p. 2705 - 2706 (1989)
Allylic alcohols are obtained with an unprecedented simple method by chemoselective hydrogen transfer reduction of α,β unsaturated ketones catalyzed by MgO.
Catalyst activation by loss of cyclopentadienyl ligands in hydrogen transfer catalysis with Cp*IrIII complexes
Campos, Jesus,Hintermair, Ulrich,Brewster, Timothy P.,Takase, Michael K.,Crabtree, Robert H.
, p. 973 - 985 (2014)
The activity of the two related complexes [Cp*Ir(IMe) 2X]BF4 (X = Cl (1), H (2)) in transfer hydrogenation from isopropyl alcohol to acetophenone was investigated. The results suggest that the commonly accepted monohydride mechanism for transfer hydrogenation mediated by cyclopentadienyl iridium species does not apply to chloride 1. We have found evidence that, although the two monodentate NHC ligands are retained in the coordination sphere, the Cp* ligand is completely released under mild conditions in a precatalytic activation step. Synthesis of modified versions of the initial precatalyst 1 with different cyclopentadienyl and NHC ligands demonstrated that increasing the steric pressure around the iridium center facilitates precatalyst activation and thus enhances the catalytic performance. Study of five new iridium(III) complexes bearing mono- or diphosphines helped us monitor Cp* ligand loss under mild conditions. An unusual P-C bond cleavage was also noted in a 1,2-bis(dimethylphosphino)methane (dmpm) ligand. On the basis of these findings, a novel catalyst activation mechanism is proposed for [(η5-C5R5)Ir] transfer hydrogenation based on the lability of the cyclopentadienyl ligand.
The conversion of 4-oxa-5-hexenyllithiums to 4-alken-1-ols: A novel [1,4]-wittig rearrangement
Bailey, William F.,Zarcone, Lyn M. J.
, p. 4425 - 4426 (1991)
4-Oxa-5-hexenyllithiums (2), which may be prepared from the corresponding 3-iodoalkyl vinyl ethers (1) by low-temperature lithium - iodine exchange, rearrange in high yield to 4-alken-1-ols (4) when warmed to room temperature. This transformation, which constitutes a [1,4]-Wittig rearrangement, is mediated by 5-exo-trig closure of 2 to a (2-tetrahydrofuranyl)methyllithium (3) followed by spontaneous ring opening to give 4.
Photopolymerization of Plasticizer in Ion-Sensitive Membranes on Solid-State Sensors
Harrison, D. Jed,Teclemariam, Alem,Cunningham, Linda L.
, p. 246 - 251 (1989)
Poyl(vinyl chloride) membranes containing the K+ ionophore valinomycin and plasticized with dihexenyl adipate (DHA) can be photopolymerized in the presence of a radical initiator.Photolysis times of 30 min result in ca. 1.5percent reaction of DHA in the presence of O2 and 8percent reaction in its absence, while 90 min is required for 7percent reaction with O2 present.Photolysis for 30 min in air results in a 3- to 5-fold increase in lifetime for membranes coated on solid-state Si sensors, despite the low extent reaction of DHA.The slope of 57.5 mV, and selectivity coefficient for K+ over Na+ of 8 X 10-5, are similar to dioctyl adipate plasiticized K+ membranes.Photolysis for 30min in the absence of O2 results in 3-fold increase in lifetime of membrane-coated Si sensors, but the success rate of electrode preparation is only 50percent.The probability that polymerization and interfacially induced stresses are a factor in membrane degradation is discussed, as is the relevance to ion-sensitive field effect transistors.
A Nazarov-Ene Tandem Reaction for the Stereoselective Construction of Spiro Compounds
Etling, Christoph,Tedesco, Giada,Kalesse, Markus
supporting information, p. 9257 - 9262 (2021/06/01)
The different reactivity of trienones under Lewis and Br?nsted acids catalysis was investigated, resulting in distinct cyclization products and carbon backbones that originated either from a conjugate Prins cyclization or an interrupted Nazarov cyclizatio
Methylene-Linked Bis-NHC Half-Sandwich Ruthenium Complexes: Binding of Small Molecules and Catalysis toward Ketone Transfer Hydrogenation
Botubol-Ares, José Manuel,Cordón-Ouahhabi, Safa,Moutaoukil, Zakaria,Collado, Isidro G.,Jiménez-Tenorio, Manuel,Puerta, M. Carmen,Valerga, Pedro
supporting information, p. 792 - 803 (2021/04/06)
The complex [Cp*RuCl(COD)] reacts with LH2Cl2 (L = bis(3-methylimidazol-2-ylidene)) and LiBun in tetrahydrofuran at 65 °C furnishing the bis-carbene derivative [Cp*RuCl(L)] (2). This compound reacts with NaBPh4 in MeOH under dinitrogen to yield the labile dinitrogen-bridged complex [{Cp*Ru(L)}2(μ-N2)][BPh4]2 (4). The dinitrogen ligand in 4 is readily replaced by a series of donor molecules leading to the corresponding cationic complexes [Cp*Ru(X)(L)][BPh4] (X = MeCN 3, H2 6, C2H4 8a, CH2CHCOOMe 8b, CHPh 9). Attempts to recrystallize 4 from MeNO2/EtOH solutions led to the isolation of the nitrosyl derivative [Cp*Ru(NO)(L)][BPh4]2 (5), which was structurally characterized. The allenylidene complex [Cp*Ru═C═C═CPh2(L)][BPh4] (10) was also obtained, and it was prepared by reaction of 2 with HCCC(OH)Ph2 and NaBPh4 in MeOH at 60 °C. Complexes 3, 4, and 6 are efficient catalyst precursors for the transfer hydrogenation of a broad range of ketones. The dihydrogen complex 6 has proven particularly effective, reaching TOF values up to 455 h-1 at catalyst loadings of 0.1% mol, with a high functional group tolerance on the reduction of a broad scope of aryl and aliphatic ketones to yield the corresponding alcohols.
Enantiopure 2,9-Dideuterodecane – Preparation and Proof of Enantiopurity
Christoffers, Jens,Eru?ar, Gülsera,Fsadni, Miriam H.,Golding, Bernard T.,Mitschke, Nico,Roberts, Amy R.,Sadeghi, Majid M.,Wilkes, Heinz
, p. 3854 - 3863 (2021/08/24)
(R,R)- and (S,S)-(2,9-2H2)-n-Decane were prepared regio- and stereospecifically in 25–26 % yield over five steps from commercially available enantiopure (R)- and (S)-propylene oxide, respectively. The synthetic procedure involved nucleophilic displacement of (R)- and (S)-4-toluenesulfonic acid 1-methyl-4-pentenyl ester with LiAlD4 to furnish the respective (5-2H)-1-hexenes. Subsequent olefin metathesis and reduction of the double bond furnished the title compounds. The optical purity of (R,R)- and (S,S)-(2,9-2H2)-n-decane could not be determined by chromatography or polarimetry. Therefore, (R,R)- and (R,S)-(5-2H)-3-hydroxy-2-hexanone were prepared from their respective hexenes by Wacker oxidation, followed by enantioselective α-hydroxylation. The enantiopurity could then be determined by NMR spectroscopy because the stereospecifically deuterated hydroxyketones showed separated signals for the subterminal carbon atom (C-5) in the 13C NMR spectrum.
Photoinduced Palladium-Catalyzed Dicarbofunctionalization of Terminal Alkynes
Yang, Zhen,Koenigs, Rene M.
supporting information, p. 3694 - 3699 (2021/02/01)
Herein, a conceptually distinct approach was developed that allowed for the dicarbofunctionalization of alkynes at room temperature using simple, bench-stable alkyl iodides and a second molecule of alkyne as coupling partner. Specifically, the photochemical activation of palladium complexes enabled this strategic dicarbofunctionalization via addition of alkyl radicals from secondary and tertiary alkyl iodides and formation of an intermediate palladium vinyl complex that could undergo subsequent Sonogashira reaction with a second alkyne molecule. This alkylation–alkynylation sequence allowed the one-step synthesis of 1,3-enynes including heteroarenes and biologically active compounds with high efficiency without exogenous photosensitizers or oxidants and now opens up pathways towards cascade reactions via photochemical palladium catalysis.
Chromium-Catalyzed Production of Diols From Olefins
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Paragraph 0111, (2021/03/19)
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
