54774-27-5Relevant articles and documents
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.
Chromium-Catalyzed Production of Diols From Olefins
-
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.
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.
Complex Carbocyclic Skeletons from Aryl Ketones through a Three-Photon Cascade Reaction
Bach, Thorsten,Jandl, Christian,N?sborg, Line,Zech, Andreas
supporting information, p. 5656 - 5659 (2020/02/11)
Starting from readily available 7-substituted 1-indanones, products with a tetracyclo[5.3.1.01,704,11]undec-2-ene skeleton were obtained upon irradiation at λ=350 nm (eight examples, 49–67 % yield). The assembly of the structurally complex carbon framework proceeds in a three-photon process comprising an ortho photocycloaddition, a disrotatory [4π] photocyclization, and a di-π-methane rearrangement. The flat aromatic core of the starting material is converted into a functionalized polycyclic hydrocarbon with exit vectors in three dimensions. Ring opening reactions at the central cyclopropane ring were explored, which enable the preparation of tricyclo[5.3.1.04,11]undec-2-enes and of tricyclo[6.2.1.01,5]undecanes.
Acetate Acetylacetonate Ampy Ruthenium(II) Complexes as Efficient Catalysts for Ketone Transfer Hydrogenation
Hey, Daniela A.,Sauer, Michael J.,Fischer, Pauline J.,Esslinger, Eva-Maria H. J.,Kühn, Fritz E.,Baratta, Walter
, p. 3537 - 3544 (2020/06/01)
The mixed acetate acetylacetonate (acac) ruthenium(II) phosphine complexes Ru(OAc)(acac)P2 [P2=(PPh3)2, Ph2P(CH2)4PPh2 (dppb)] were prepared by protonation of Ru(OAc)2(PPh3)2 with acetylacetone in dichloromethane. Reaction of the dppb derivative with 2-(aminomethyl)pyridine (ampy) affords the complex Ru(OAc)(acac)(ampy)(dppb), which converts to [Ru(acac)(ampy)(dppb)](OAc) in toluene at 90 °C. In the former derivative the ampy ligand is monodentate and coordinates through the NH2-moiety. The isolated acac complexes are active catalysts for the transfer hydrogenation of ketones with loadings as low as 0.01 mol%, the ampy having a strong accelerating effect. Several aromatic and aliphatic ketone substrates are converted to their corresponding alcohols, and different electronic influences through substituents on acetophenone are tolerated.
Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
supporting information, p. 14286 - 14294 (2020/09/15)
A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
Base-free transfer hydrogenation of aryl-ketones, alkyl-ketones and alkenones catalyzed by an IrIIICp* complex bearing a triazenide ligand functionalized with pyrazole
Medrano-Castillo, Layla J.,Collazo-Flores, Miguel á.,Camarena-Díaz, Juan P.,Correa-Ayala, Erick,Chávez, Daniel,Grotjahn, Douglas B.,Rheingold, Arnold L.,Miranda-Soto, Valentín,Parra-Hake, Miguel
, (2020/03/13)
An IrIIICp* complex (2) bearing a triazenide ligand functionalized with pyrazole was synthesized and fully characterized by spectroscopic methods and the structure confirmed by X-ray diffraction studies. The catalytic activity of 2 and the control complex 3, which lacks of pyrazole in its structure, was evaluated in the reduction of aryl-ketones, alkyl-ketones, α,β-unsaturated and γ,δ-unsaturated ketones. The catalytic system, using either 2 or 3, exhibited good to excellent selectivity when tested with ketones and alkenones at 90 °C in 2-propanol as hydrogen source under base-free conditions. Reactivity of 2 in 2-propanol and NaH gave a neutral metal hydride (4) while in the absence of base gave two major cationic hydrides species (5 and 6).
Silica-Supported MnII Sites as Efficient Catalysts for Carbonyl Hydroboration, Hydrosilylation, and Transesterification
Ghaffari, Behnaz,Mendes-Burak, Jorge,Chan, Ka Wing,Copéret, Christophe
supporting information, p. 13869 - 13873 (2019/11/11)
Manganese, the third most abundant transition-metal element after iron and titanium, has recently been demonstrated to be an effective homogeneous catalyst in numerous reactions. Herein, the preparation of silica-supported MnII sites is reported using Surface Organometallic Chemistry (SOMC), combined with tailored thermolytic molecular precursors approach based on Mn2[OSi(OtBu)3]4 and Mn{N(SiMe3)2}2?THF. These supported MnII sites, free of organic ligands, efficiently catalyze numerous reactions: hydroboration and hydrosilylation of ketones and aldehydes as well as the transesterification of industrially relevant substrates.
