928-97-2Relevant academic research and scientific papers
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.
Highly Regioselective 5-endo-tet Cyclization of 3,4-Epoxy Amines into 3-Hydroxypyrrolidines Catalyzed by La(OTf)3
Hoshino, Yoshihiko,Iwabuchi, Yoshiharu,Kuriyama, Yuse,Sasano, Yusuke,Uesugi, Shun-ichiro,Yamaichi, Aoto
supporting information, p. 1961 - 1965 (2021/01/04)
Highly regioselective intramolecular aminolysis of 3,4-epoxy amines has been achieved. Key features of this reaction are (1) chemoselective activation of epoxides in the presence of unprotected aliphatic amines in the same molecules by a La(OTf)3 catalyst and (2) excellent regioselectivity for anti-Baldwin 5-endo-tet cyclization. This reaction affords 3-hydroxy-2-alkylpyrrolidines stereospecifically in high yields. DFT calculations revealed that the regioselectivity might be attributed to distortion energies of epoxy amine substrates. The use of this reaction was demonstrated by the first enantioselective synthesis of an antispasmodic agent prifinium bromide.
MIXTURE OF 3-HEXEN-1-OL ISOMERS AND A PROCESS OF PREPARING SAME
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Page/Page column 21-22, (2021/08/14)
Compositions comprising 3-hexen-l-ol are described herein, as well as odor-imparting formulations comprising same and articles-of-manufacturing comprising such compositions or odor-imparting formulations. The compositions comprise trans- 3-hexen-l-ol in a range of from 67 % to 82 % by weight and cA-3-hexen-l-ol in a range of from 18 % to 33 % by weight, wherein a total concentration of trans- 3-hexen-l-ol and cA-3-hexen-l-ol is at least 97 % by weight. Further described herein is a process for preparing a composition comprising 3-hexen-l-ol, the process comprising: contacting 1-pentene with a formaldehyde in the presence of a Lewis acid to thereby obtain a crude mixture comprising 3-hexen-l-ol; and contacting the mixture comprising 3-hexen- l-ol with a base.
ENVIRONMENTALLY-FRIENDLY HYDROAZIDATION OF OLEFINS
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Page/Page column 97-98, (2020/01/24)
The present invention provides processes for the synthesis of organic azides, intermediates for the production thereof, and compositions related thereto.
Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
, p. 2278 - 2290 (2019/06/17)
A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
A General One-Pot Methodology for the Preparation of Mono- and Bimetallic Nanoparticles Supported on Carbon Nanotubes: Application in the Semi-hydrogenation of Alkynes and Acetylene
Lomelí-Rosales, Diego A.,Delgado, Jorge A.,Díaz de los Bernardos, Miriam,Pérez-Rodríguez, Sara,Gual, Aitor,Claver, Carmen,Godard, Cyril
supporting information, p. 8321 - 8331 (2019/06/04)
A facile and straightforward methodology for the preparation of monometallic (copper and palladium) and bimetallic nanocatalysts (NiCu and PdCu) stabilized by a N-heterocyclic carbene ligand is reported. Both colloidal and supported nanoparticles (NPs) on carbon nanotubes (CNTs) were prepared in a one-pot synthesis with outstanding control on their size, morphology and composition. These catalysts were evaluated in the selective hydrogenation of alkynes and alkynols. PdCu/CNTs revealed an efficient catalytic system providing high selectivity in the hydrogenation of terminal and internal alkynes. Moreover, this catalyst was tested in the semi-hydrogenation of acetylene in industrially relevant acetylene/ethylene-rich model gas feeds and showed excellent stability even after 40 h of reaction.
Catalytic Regio- and Enantioselective Oxytrifluoromethylthiolation of Aliphatic Internal Alkenes by Neighboring Group Assistance
Xu, Jia,Zhang, Yuanyuan,Qin, Tian,Zhao, Xiaodan
supporting information, p. 6384 - 6388 (2018/10/09)
Chiral selenide-catalyzed oxytrifluoromethylthiolation of aliphatic internal alkenes by a formally intermolecular strategy is disclosed, affording CF3S 1,3-amino alcohol and 1,3-diol derivatives with high regio-, enantio-, and diastereoselectivities. The reactions are promoted by a neighboring imide or ester group on substrates via a six-membered ring transition state. This assistance strategy is also successfully applied to the regio- and diastereoselective oxyhalofunctionalization of internal alkenes and the conversion of alkynes.
Iron-Catalyzed Direct Olefin Diazidation via Peroxyester Activation Promoted by Nitrogen-Based Ligands
Shen, Shou-Jie,Zhu, Cheng-Liang,Lu, Deng-Fu,Xu, Hao
, p. 4473 - 4482 (2018/05/22)
We herein report an iron-catalyzed direct diazidation method via activation of bench-stable peroxyesters promoted by nitrogen-based ligands. This method is effective for a broad range of olefins and N-heterocycles, including those that are difficult substrates for the existing olefin diamination and diazidation methods. Notably, nearly a stoichiometric amount of oxidant and TMSN3 are sufficient for high-yielding diazidation for most substrates. Preliminary mechanistic studies elucidated the similarities and differences between this method and the benziodoxole-based olefin diazidation method previously developed by us. This method effectively addresses the limitations of the existing olefin diazidation methods. Most notably, previously problematic nonproductive oxidant decomposition can be minimized. Furthermore, X-ray crystallographic studies suggest that an iron-azide-ligand complex can be generated in situ from an iron acetate precatalyst and that it may facilitate peroxyester activation and the rate-determining C-N3 bond formation during diazidation of unstrained olefins.
Gold-Ligand-Catalyzed Selective Hydrogenation of Alkynes into cis-Alkenes via H2 Heterolytic Activation by Frustrated Lewis Pairs
Fiorio, Jhonatan L.,López, Núria,Rossi, Liane M.
, p. 2973 - 2980 (2017/05/31)
The selective hydrogenation of alkynes to alkenes is an important synthetic process in the chemical industry. It is commonly accomplished using palladium catalysts that contain surface modifiers, such as lead and silver. Here we report that the adsorption of nitrogen-containing bases on gold nanoparticles results in a frustrated Lewis pair interface that activates H2 heterolytically, allowing an unexpectedly high hydrogenation activity. The so-formed tight-ion pair can be selectively transferred to an alkyne, leading to a cis isomer; this behavior is controlled by electrostatic interactions. Activity correlates with H2 dissociation energy, which depends on the basicity of the ligand and its reorganization on activation of hydrogen. High surface occupation and strong Au atom-ligand interactions might affect the accessibility and stability of the active site, making the activity prediction a multiparameter function. The promotional effect found for nitrogen-containing bases with two heteroatoms was mechanistically described as a strategy to boost gold activity. (Graph Presented).
Selective hydrogenation of 3-Hexyn-1-ol with Pd nanoparticles synthesized via microemulsions
Montsch, Thomas,Heuchel, Moritz,Traa, Yvonne,Klemm, Elias,Stubenrauch, Cosima
, p. 19 - 28 (2017/04/13)
In the study at hand we present a design strategy for novel catalysts which can be used for the selective hydrogenation of alkynes to alkenes. The design of the novel catalysts is based on two main ideas, namely (1) the synthesis of Pd nanoparticles via microemulsions and (2) the use of highly-ordered mesoporous silica with a 3-D pore network (FDU-12) serving as support. The nanoparticles are deposited on FDU-12 in two different ways. Firstly, we simply impregnated the support with a dispersion of the nanoparticles. The resulting catalyst was not selective at all; on the contrary, it fully hydrogenated our model alkyne, namely 3-hexyn-1-ol. Secondly, we synthesized the FDU-12 in the presence of the nanoparticles (in-situ synthesis). In this case, we obtained one catalyst which performed as well as the Lindlar catalyst although the metal content was slightly lower and our catalyst contained no Pb. Another catalyst of the same series, prepared in the presence of another stabilizer, performed as well as the NanoSelect catalyst but at a 7 times higher metal content. For the sake of comparison we also impregnated FDU-12 via classical incipient wetness impregnation and again obtained a completely nonselective catalyst. Our results demonstrate that the in-situ synthesis has great potential as regards the development of novel catalysts.
