14952-06-8Relevant academic research and scientific papers
Ordered Porous Pd Octahedra Covered with Monolayer Ru Atoms
Ge, Jingjie,He, Dongsheng,Bai, Lei,You, Rui,Lu, Haiyuan,Lin, Yue,Tan, Chaoliang,Kang, Yan-Biao,Xiao, Bin,Wu, Yuen,Deng, Zhaoxiang,Huang, Weixin,Zhang, Hua,Hong, Xun,Li, Yadong
, p. 14566 - 14569 (2015)
Monolayer Ru atoms covered highly ordered porous Pd octahedra have been synthesized via the underpotential deposition and thermodynamic control. Shape evolution from concave nanocube to octahedron with six hollow cavities was observed. Using aberration-corrected high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy, we provide quantitative evidence to prove that only a monolayer of Ru atoms was deposited on the surface of porous Pd octahedra. The as-prepared monolayer Ru atoms covered Pd nanostructures exhibited excellent catalytic property in terms of semihydrogenation of alkynes.
Ir-Catalyzed Remote Functionalization by the Combination of Deconjugative Chain-Walking and C-H Activation Using a Transient Directing Group
Tang, King Hung Nigel,Uchida, Kanako,Nishihara, Kazuki,Ito, Mamoru,Shibata, Takanori
supporting information, p. 1313 - 1317 (2022/02/23)
An Ir-catalyzed reaction of N-benzylideneanilines with functionalized alkenes such as α,β-unsaturated esters gave ortho-substituted benzaldehyde derivatives with a functional group at the remote position after acidic treatment. The present transformation
Ligand-controlled cobalt-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes
Huang, Jiaxin,Li, Jie,Yang, Wen,Zhang, Kezhuo,Zhao, Pei,Zhao, Wanxiang
supporting information, p. 302 - 305 (2022/01/03)
The Co-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes were realized by a ligand-controlled strategy. The remote hydroboration with dcype provided borylethers, while xantphos favored the formation of silyl enol ethers.
CYCLOALKYL-CONTAINING CARBOXYLIC ACIDS AND USES THEREOF
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Page/Page column 47; 89, (2021/06/26)
The present application discloses a compound of formula (I) or a salt thereof: (I) and compositions comprising such compound or salt thereof. The use of such compound, salt thereof or composition comprising same for treating anemia or leukopenia, fibrosis, cancer, hypertension and/or a metabolic condition in a subject is also disclosed.
Phosphetane oxides as redox cycling catalysts in the catalytic wittig reaction at room temperature
Longwitz, Lars,Spannenberg, Anke,Werner, Thomas
, p. 9237 - 9244 (2019/10/08)
Recently, phosphorus redox cycling has gained significant importance for a number of transformations originally requiring the use of stoichiometric amounts of phosphorus reagents. While these methodologies have several benefits, high catalyst loadings (≥10 mol percent) and harsh reaction conditions (T ≥ 100 °C) often limit their versatility and applicability. Herein, we report differently substituted phosphetane oxides as efficient catalysts for the catalytic Wittig reaction. The phosphetane scaffold is easy to modify, and a number of catalysts can be obtained in a simple two-step synthesis. The activity in the Wittig reaction significantly surpasses previously reported phospholane-based catalysts and the reaction can be conducted with catalyst loadings as low as 1.0 mol percent even at room temperature. Furthermore, a Br?nsted acid additive is no longer required to achieve high yields at these mild conditions. A methyl-substituted phosphetane oxide was employed to synthesize 25 different alkenes with yields of up to 97percent. The methodology has a good functional group tolerance and the reaction can be performed starting with alkyl chlorides, bromides, or iodides. Additionally, it was possible to use poly(methylhydrosiloxane) as the terminal reductant in the catalytic Wittig reaction employing 2-MeTHF as a renewable solvent. The intermediates of the Wittig reaction were analyzed by 31P NMR spectroscopy, and in situ NMR experiments confirmed phosphane oxide as the resting state of the catalyst. Further kinetic investigations revealed a striking influence of the base on the rate of phosphane oxide reduction.
Electrophilic Iron Catalyst Paired with a Lithium Cation Enables Selective Functionalization of Non-Activated Aliphatic C?H Bonds via Metallocarbene Intermediates
Hernán-Gómez, Alberto,Rodríguez, Mònica,Parella, Teodor,Costas, Miquel
, p. 13904 - 13911 (2019/08/30)
Combining an electrophilic iron complex [Fe(Fpda)(THF)]2 (3) [Fpda=N,N′-bis(pentafluorophenyl)-o-phenylenediamide] with the pre-activation of α-alkyl-substituted α-diazoesters reagents by LiAl(ORF)4 [ORF=(OC(CF3)3] provides unprecedented access to selective iron-catalyzed intramolecular functionalization of strong alkyl C(sp3)?H bonds. Reactions occur at 25 °C via α-alkyl-metallocarbene intermediates, and with activity/selectivity levels similar to those of rhodium carboxylate catalysts. Mechanistic investigations reveal a crucial role of the lithium cation in the rate-determining formation of the electrophilic iron-carbene intermediate, which then proceeds by concerted insertion into the C?H bond.
Novel multi-dentate phosphines for Pd-catalyzed alkoxycarbonylation of alkynes promoted by H2O additive
Yang, Da,Liu, Lei,Wang, Dong-Liang,Lu, Yong,Zhao, Xiao-Li,Liu, Ye
, p. 236 - 244 (2019/02/19)
A series of novel multi (bi-/tri-/tetra-)-dentate phosphines with good robustness against water and oxygen were synthesized and fully characterized. It was found that the developed ionic tri-dentate phosphine (L2′) enabled Pd-catalyzed alkoxycarbonylation of alkynes most efficiently while H2O was used as an additive instead of acid. As for L2′, its unique steric configuration with two types of potential P-P chelation modes (P?P distance of 4.31 ? and 4.36 ? respectively) to Pd-centre rendered the corresponding Pd-catalyst high activity and good stability for alkoxycarbonylation of alkynes. The in situ FT-IR analysis also verified that the formation and stability of Pd–H active species were greatly facilitated with the presence of L2′ as well as H2O additive. In addition, as an ionic phosphine, L2′ based PdCl2(MeCN)2 system immobilized in RTIL of [Bmim]NTf2 could be recycled for 7 runs without obvious activity loss or metal leaching.
Mechanochemical enzymatic resolution of N-benzylated-β3-amino esters
Pérez-Venegas, Mario,Reyes-Rangel, Gloria,Neri, Adrián,Escalante, Jaime,Juaristi, Eusebio
supporting information, p. 1728 - 1734 (2017/09/27)
The use of mechanochemistry to carry out enantioselective reactions has been explored in the last ten years with excellent results. Several chiral organocatalysts and even enzymes have proved to be resistant to milling conditions, which allows for rather efficient enantioselective transformations under ball-milling conditions. The present article reports the first example of a liquid-assisted grinding (LAG) mechanochemical enzymatic resolution of racemic β3-amino esters employing Candida antarctica lipase B (CALB) to afford highly valuable enantioenriched N-benzylated-β3-amino acids in good yields. Furthermore the present protocol is readily scalable.
A highly efficient Pd/CuI-catalyzed oxidative alkoxycarbonylation of α-olefins to unsaturated esters
Maffei, Mathias,Giacoia, Gabriele,Mancuso, Raffaella,Gabriele, Bartolo,Motti, Elena,Costa, Mirco,Della Ca’, Nicola
, p. 435 - 443 (2016/12/16)
A new protocol for the alkoxycarbonylation of α-olefins to the corresponding unsaturated esters has been developed. Differently substituted styrenes were selectively converted to cinnamate derivatives, via C[sbnd]H bond functionalization. Various palladium sources, including heterogeneous ones, in combination with CuI exhibited a high catalytic efficiency using oxygen as the most cheap oxidant. Monocarbonylated products were obtained in good yields and high chemoselectivity working with a low CO pressure (2 atm) and an excess of air (35 atm) avoiding in this way explosion risks. Commercial cinnamate derivatives were prepared in good to excellent yields by this very simple one-pot procedure.
Upgrading castor oil: From heptanal to non-isocyanate poly(amide-hydroxyurethane)s
Ruiz,Aghmiz,Masdeu-Bultó,Lligadas,Ronda,Galià,Cádiz
, p. 226 - 234 (2017/08/07)
Intensive research has recently been carried out to synthesize non-isocyanate polyurethanes (NIPUs) from five-membered cyclic carbonates and amines as a sustainable route to industrial relevant polyurethanes. Herein, an activated disubstituted cyclic carbonate and methyl ester containing monomer CE was prepared using castor oil based heptanal and CO2. Good results for the catalytic cycloaddition have been obtained using renewable sugar cane bagasse in combination with TBAB, and this system has been shown to be recyclable. A novel poly(amide-hydroxyurethane) (PAHU) was obtained by bulk ring-opening and amidation polymerization of high reactive CE with 1,6-diaminohexane at low temperature and in absence of catalyst. PAHU contains aliphatic pendant moieties allowing its self-assembling into nanoparticles in aqueous solution, showing potential application in catalysis or drug delivery among other applications.
