395-45-9Relevant academic research and scientific papers
KO-t-Bu Catalyzed Thiolation of β-(Hetero)arylethyl Ethers via MeOH Elimination/hydrothiolation
Shigeno, Masanori,Shishido, Yoshiteru,Hayashi, Kazutoshi,Nozawa-Kumada, Kanako,Kondo, Yoshinori
supporting information, p. 3932 - 3935 (2021/08/24)
Herein, we describe a KO-t-Bu catalyzed thiolation of β-(hetero)arylethyl ethers through MeOH elimination to form (hetero)arylalkenes followed by anti-Markovnikov hydrothiolation to afford linear thioethers. The system works well with a variety of β-(hetero)arylethyl ethers, including electron-deficient, electron-neutral, electron-rich, and branched substrates and a range of aliphatic and aromatic thiols.
Deoxygenation of Epoxides with Carbon Monoxide
Maulbetsch, Theo,Jürgens, Eva,Kunz, Doris
, p. 10634 - 10640 (2020/07/30)
The use of carbon monoxide as a direct reducing agent for the deoxygenation of terminal and internal epoxides to the respective olefins is presented. This reaction is homogeneously catalyzed by a carbonyl pincer-iridium(I) complex in combination with a Lewis acid co-catalyst to achieve a pre-activation of the epoxide substrate, as well as the elimination of CO2 from a γ-2-iridabutyrolactone intermediate. Especially terminal alkyl epoxides react smoothly and without significant isomerization to the internal olefins under CO atmosphere in benzene or toluene at 80–120 °C. Detailed investigations reveal a substrate-dependent change in the mechanism for the epoxide C?O bond activation between an oxidative addition under retention of the configuration and an SN2 reaction that leads to an inversion of the configuration.
Selective Semi-Hydrogenation of Terminal Alkynes Promoted by Bimetallic Cu-Pd Nanoparticles
Buxaderas, Eduardo,Volpe, María Alicia,Radivoy, Gabriel
, p. 1466 - 1472 (2019/03/07)
The selective semi-hydrogenation of terminal alkynes was efficiently performed, under mild reaction conditions (H 2 balloon, 110 °C), promoted by a bimetallic nanocatalyst composed of copper and palladium nanoparticles (5:1 weight ratio) supported on mesostructured silica (MCM-48). The Cu-PdNPS@MCM-48 catalyst, which demonstrated to be highly chemoselective towards the alkyne functionality, is readily prepared from commercial materials and can be recovered and reused after thermal treatment followed by reduction under H 2 atmosphere.
An Interrupted Pummerer/Nickel-Catalysed Cross-Coupling Sequence
Aukland, Miles H.,Talbot, Fabien J. T.,Fernández-Salas, José A.,Ball, Matthew,Pulis, Alexander P.,Procter, David J.
supporting information, p. 9785 - 9789 (2018/07/31)
An interrupted Pummerer/nickel-catalysed cross-coupling strategy has been developed and used in the elaboration of styrenes. The operationally simple method can be carried out as a one-pot process, involves the direct formation of stable alkenyl sulfonium salt intermediates, utilises a commercially available sulfoxide, catalyst, and ligand, operates at ambient temperature, accommodates sp-, sp2-, and sp3-hybridised organozinc coupling partners, and delivers functionalised styrene products in high yields over two steps. An interrupted Pummerer/cyclisation approach has also been used to access carbo- and heterocyclic alkenyl sulfonium salts for cross-coupling.
A Pd-Cu2O nanocomposite as an effective synergistic catalyst for selective semi-hydrogenation of the terminal alkynes only
Yang, Shuliang,Cao, Changyan,Peng, Li,Zhang, Jianling,Han, Buxing,Song, Weiguo
supporting information, p. 3627 - 3630 (2016/03/05)
A new type lead-free catalyst of a Pd-Cu2O nanocomposite was developed for highly selective semi-hydrogenation of alkynes. With unprecedented selectivity for the semi-hydrogenation of terminal alkynes to alkenes, we show for the first time that the catalyst only hydrogenated the terminal alkynes, i.e. did not hydrogenate the internal alkynes.
The ionic liquid microphase enhances the catalytic activity of Pd nanoparticles supported by a metal-organic framework
Peng, Li,Zhang, Jianling,Yang, Shuliang,Han, Buxing,Sang, Xinxin,Liu, Chengcheng,Yang, Guanying
supporting information, p. 4178 - 4182 (2015/08/11)
Here we demonstrate the utilization of the ionic liquid (IL) microphase for enhancing the catalytic activities of the metal nanoparticles supported on a MOF. The IL microphase offers an excellent environment for stabilizing metal nanoparticles. A new heterogeneous catalyst Pd/IL/MOF is developed, which combines the advantages of highly dispersed small Pd nanoparticles, the IL microphase and a porous MOF. The as-synthesized Pd/IL/MOF catalysts have shown high catalytic activity and reusability for selective hydrogenation under mild conditions.
Heck, Sonogashira, and Hiyama reactions catalyzed by palladium nanoparticles stabilized by tris-imidazolium salt
Planellas, Marc,Moglie, Yanina,Alonso, Francisco,Yus, Miguel,Pleixats, Roser,Shafir, Alexandr
supporting information, p. 3001 - 3008 (2014/05/20)
Palladium nanoparticles, prepared by the hydrogenation of Pd(dba) 2 in the presence of a tris-imidazolium iodide as stabilizer, act as an efficient catalyst for Heck and copper-free Sonogashira reactions with a range of aryl iodides and bromides at 0.2 mol-% Pd loading. Moreover, we describe a convenient protocol for the fluoride-free Hiyama coupling of vinylsilanes with aryl iodides that involves the use of sodium hydroxide as promoter in a methanol/water mixture. Under the developed conditions, one-pot, double Heck and Hiyama-Heck reactions are successfully achieved.
Dual Pd and CuFe2O4 nanoparticles encapsulated in a core/shell silica microsphere for selective hydrogenation of arylacetylenes
Lee, Kyu Hyung,Lee, Byeongno,Lee, Kyu Reon,Yi, Mi Hye,Hur, Nam Hwi
supporting information; scheme or table, p. 4414 - 4416 (2012/05/20)
A dual catalyst containing Pd and CuFe2O4 nanoparticles in a silica shell exhibits >98% conversion of arylacetylenes to related styrenes with selectivity greater than 98%, which are better than those obtained using a commercial Lindlar catalyst. The excellent synergy was likely a result of the proximal interaction between Pd and CuFe2O 4 nanoparticles.
Synthesis and characterization of trifluoromethyl substituted styrene polymers and copolymers with methacrylates: Effects of trifluoromethyl substituent on styrene
Teng, Hongxiang,Lou, Liping,Koike, Kotaro,Koike, Yasuhiro,Okamoto, Yoshi
body text, p. 949 - 953 (2012/02/05)
2-Trifluoromethyl styrene (2TFMS), 2,5-bis(trifluoromethyl) styrene (25BTFMS), and 3,5-bis(trifluoromethyl) styrene (35BTFMS) were synthesized. These styrenes were readily polymerized in bulk and also in solution using AIBN as a free radical initiator. The polymerization rate of these trifluoromethyl substituted styrenes and other monomers such as styrene (St), pentafluorostyrene (PFS) and 4-trifluoromethyl-tetrafluorostyrene (TFMTFS) were measured in benzene and dioxane by monitoring the 1H NMR spectra of the double bond hydrogen. The order of polymerization rates was TFMTFS > 35BTFMS > 25BTFMS > PFS > 2TFMS > St. Tgs of styrene polymers with CF3 substituted on the ortho position of the phenyl ring were much higher than those of the meta and para substituted styrenes due to the steric hindrance of the bulky CF3 group close to the polymer main chain, which resulted in a decrease in the segment mobility of the polymer chains and an increasing Tg of the polymers. The copolymers of 2TFMS with methyl methacrylate (MMA) and also 25BTFMS with trifluoroethyl methacrylate (TFEMA) were prepared. Tgs of the copolymers were in the range of 120-145 °C and the copolymers were transparent and thermally stable. The copolymer films were flexible and exhibited high transmittance as the homopolymers of MMA and TFEMA. Thus, these copolymers may be utilized as novel optical materials.
Vinylation of aromatic halides using inexpensive organosilicon reagents. Illustration of design of experiment protocols
Denmark, Scott E.,Butler, Christopher R.
, p. 3690 - 3704 (2008/10/09)
The preparation of styrenes by palladium-catalyzed cross-coupling of aromatic iodides and bromides with divinyltetramethyldisiloxane (DVDS) in the presence of inexpensive silanolate activators has been developed. To facilitate the discovery of optimal reaction conditions, Design of Experiment (DoE) protocols were used. By the guided selection of reagents, stoichiometries, temperatures, and solvents, the vinylation reaction was rapidly optimized with three stages consisting of ca. 175 experiments (of a possible 1440 combinations). A variety of aromatic iodides undergo cross-coupling at room temperature in the presence of potassium trimethylsilanoate using Pd(dba) 2 in DMF in good yields. Triphenylphosphine oxide is needed to extend catalyst lifetime. Application of these conditions to aryl bromides was accomplished by the development of two complementary protocols. First, the direct implementation of the successful reaction conditions using aryl iodides at elevated temperature in THF provided the corresponding styrenes in good to excellent yields. Alternatively, the use of potassium triethylsilanolate and a bulky "Buchwald-type" ligand allows for the vinylation reactions to occur at or just above room temperature. A wide range of bromides underwent coupling in good yields for each of the protocols described.
