2944-48-1Relevant academic research and scientific papers
Catalysis by 12-Heteropolymolybdic Acid. II. Friedel-Crafts-type Reaction of Aromatic Compounds
Nomiya, Kenji,Sugaya, Yoshio,Sasa, Sadayoshi,Miwa, Makoto
, p. 2089 - 2090 (1980)
12-Heteropolymolybdic acid, a heteropolyacid of Keggin-structure, behaves as an effective catalyst of the Friedel-Crafts-type reactions for aromatic compounds, such as alkylation by benzyl chloride and t-butyl chloride, acylation by acetyl chloride, and sulfonylation by tosyl chloride.The catalyst mainly gives para-substiuted products for phenol and anisole.The reactions proceed via carbocation-generation mechanism brought about by the strong Broensted acid.
S,O-Ligand-Promoted Pd-Catalyzed C?H Olefination of Anisole Derivatives
Fernández-Ibá?ez, M. ángeles,Jia, Wen-Liang,Sukowski, Verena,van Borselen, Manuela,van Diest, Rianne
supporting information, p. 4132 - 4135 (2021/08/24)
The C?H olefination of substituted anisole derivatives by a Pd/S,O-ligand catalyst is reported. The reaction proceeds under mild conditions with a broad range of substituted aryl ethers bearing both electron donating and withdrawing substituents at ortho,
An N-heterocyclic carbene-based nickel catalyst for the Kumada–Tamao–Corriu coupling of aryl bromides and tertiary alkyl Grignard reagents
Ando, Shin,Mawatari, Mai,Matsunaga, Hirofumi,Ishizuka, Tadao
supporting information, p. 3287 - 3290 (2016/07/11)
In this study, nickel-catalyzed coupling reactions between arylhalides and tert-alkyl Grignard reagents were developed. Our original bicyclic NHC ligands reduced the formation of isomerized products, and we found that NMP as a co-solvent suppressed the reduction process. Under the optimal conditions we developed, the catalyst loading was lowered to 0.5?mol?%, and catalyst loading using ortho-substituted aryl bromides was also applicable at the level of 2.0?mol?%.
Palladium-Catalyzed, tert-Butyllithium-Mediated Dimerization of Aryl Halides and Its Application in the Atropselective Total Synthesis of Mastigophorene A
Buter, Jeffrey,Heijnen, Dorus,Vila, Carlos,Hornillos, Valentín,Otten, Edwin,Giannerini, Massimo,Minnaard, Adriaan J.,Feringa, Ben L.
supporting information, p. 3620 - 3624 (2016/03/23)
A palladium-catalyzed direct synthesis of symmetric biaryl compounds from aryl halides in the presence of tBuLi is described. In situ lithium-halogen exchange generates the corresponding aryl lithium reagent, which undergoes a homocoupling reaction with a second molecule of the aryl halide in the presence of the palladium catalyst (1 mol %). The reaction takes place at room temperature, is fast (1 h), and affords the corresponding biaryl compounds in good to excellent yields. The application of the method is demonstrated in an efficient asymmetric total synthesis of mastigophorene A. The chiral biaryl axis is constructed with an atropselectivity of 9:1 owing to catalyst-induced remote point-to-axial chirality transfer. It takes two: A palladium-catalyzed direct homocoupling of aryl halides in the presence of tBuLi enabled the synthesis of even tetra-ortho-substituted symmetric biaryl compounds in high yield (see scheme). The method was applied to the asymmetric synthesis of mastigophorene A in just eight steps through straightforward enantioselective installation of the benzylic quaternary stereocenter and highly diastereoselective homocoupling.
New catalyst system for producing polyethylene copolymers in a high temperature solution polymerization process
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, (2015/11/09)
Catalyst system for producing ethylene copolymers in a high temperature solution process, the catalyst system comprising (i) a metallocene complex of formula (I) wherein M is Hf or Zr X is a sigma ligand L is a bridge of the formula -SiR72
NOVEL AND SPECIFIC INHIBITORS OF CYTOCHROME P450 26 RETINOIC ACID HYDROLASE
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Page/Page column 58; 59, (2015/03/13)
The present disclosure is generally directed to compositions and methods for treating diseases that are ameliorated by the inhibition of CYP26 mediated retinoic acid metabolism.
Phase-transfer and other types of catalysis with cyclopropenium ions
Bandar, Jeffrey S.,Tanaset, Anont,Lambert, Tristan H.
supporting information, p. 7365 - 7368 (2015/05/13)
Abstract This work establishes the cyclopropenium ion as a viable platform for efficient phase-transfer catalysis of a diverse range of organic transformations. The amenability of these catalysts to large-scale synthesis and structural modification is demonstrated. Evaluation of the molecular structure of an optimal catalyst reveals some unique structural features of these systems. Finally, a discussion of electronic charge distribution underscores an important consideration for catalyst design. Aromatic ions: Tris(dialkylamino)cyclopropenium ions are shown to be effective carbocationic phase-transfer catalysts for a variety of mainstay transformations. The cyclopropenium platform is shown to be modular and accessible on scale. An X-ray structure and electron-density map revealed some unique features of this architecture (see scheme).
Bridged metallocene catalysts
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Page/Page column, (2015/07/22)
A solid, particulate catalyst comprising: (i) a complex of formula (I) wherein M is zirconium or hafnium; each X is a sigma ligand; L is a divalent bridge selected from —R′2C—, —R′2C—CR′2—, —R′2Si—, —R′2Si—SiR′2—, —R′2Ge—, wherein each R′ is independently a hydrogen atom, C1-C20-hydrocarbyl, tri(C1-C20-alkyl)silyl, C6-C20-aryl, C7-C20-arylalkyl or C7-C20-alkylaryl; each R1 is a C4-C20 hydrocarbyl radical branched at the β-atom to the cyclopentadienyl ring, optionally containing one or more heteroatoms belonging to groups 14-16, or is a C3-C20 hydrocarbyl radical branched at the β-atom to the cyclopentadienyl ring where the β-atom is an Si-atom; each R18 is a C1-C20 hydrocarbyl radical optionally containing one or more heteroatoms belonging to groups 14-16; each R4 is a hydrogen atom or a C1-6-hydrocarbyl radical; each W is a 5 or 6 membered aryl or heteroaryl ring wherein each atom of said ring is optionally substituted with at least one R5 group; each R5 is the same or different and is a C1-C20 hydrocarbyl radical optionally containing one or more heteroatoms belonging to groups 14-16; and optionally two adjacent R5 groups taken together can form a further mono or multicyclic ring condensed to W optionally substituted by one or two groups R5; and each R7 is a C1-C20 hydrocarbyl radical; and (ii) a cocatalyst, preferably comprising an organometallic compound of a Group 13 metal.
Indium(III) triflate - A catalyst for greener aromatic alkylation reactions
Mack, Ryan,Askins, Grant,Lowry, Jacob,Hurley, Nathan,Reeves, Perry C.
, p. 1262 - 1265 (2014/01/06)
An environmentally friendly method for alkylating aromatic compounds with simple alcohols in the presence of a catalytic amount of indium(III) triflate is reported. Ionic liquids are used as solvents and energy-efficient heating is provided by microwave radiation. Good yields are obtained with benzyl, secondary, and tertiary alcohols. Simple primary alcohols are not effective alkylating agents under these conditions. With tertiary alcohols, activated aromatic compounds such as toluene and anisole must be used to obtain good yields. The catalyst, which is immobilized in a water-insoluble ionic liquid, can be easily recycled without significant loss of activity.
Properties and reactivity of zinc-folded sheet mesoporous materials
Laribi,Chenouf,Bachari,Hamani
, p. 1771 - 1780 (2013/07/05)
Mesoporous material incorporating zinc with different Si/Zn ratios = 95, 65, and 20 have been synthesized by intercalating kanemite using cetyltrimethylammonium bromide as the intercalating agent and zinc nitrate. The resulting materials were characterized by different techniques such as: inductively coupled plasma technique, XRD, Brunauer-Emmett-Teller, and a temperature-programmed-desorption of pyridine. The catalytic performance was studied in the vapor phase tert-butylation of anisole with tert-butanol at different temperatures under atmospheric pressure. The results indicate that Zn-FSM-16 (20) was found to be more active than its relatives. The major products are found to be 4-tert-butyl anisole (4-TBA), 2-tert-butyl anisole (2-TBA) and 2,4 di-tert-butyl-anisole (2,4-DTBA).
