2489-86-3Relevant articles and documents
Solvent-controlled intramolecular excimer emission from organosilicon derivatives of naphthalene
Alfimov, M. V.,Anisimov, A. A.,Belova, A. S.,Ionov, D. S.,Kononevich, Yu. N.,Muzafarov, A. M.,Safonov, A. A.,Sazhnikov, V. A.,Shchegolikhina, O. I.
, (2021)
New mono-, bis- and tetra-fluorophoric organosilicon naphthalene derivatives, that are able to form intramolecular excimers have been synthesized and characterized. The synthesized compounds show only monomeric fluorescence in dilute solutions of common organic solvents, but exhibit relatively strong excimer-like emission in DMSO-water and THF-water mixtures. In all cases, the intensity of excimer fluorescence increases with increasing water content and decreases with increasing temperature. Fully and partially overlapping excimer conformations have been modeled by DFT-based calculations. Properties of different intramolecular excimers in an ensemble of four naphthalene molecules linked to a cyclotetrasiloxane ring in an all-cis arrangement are considered.
Modular Ni(0)/Silane Catalytic System for the Isomerization of Alkenes
Chang, Alison Sy-Min,Cook, Amanda K.,Kawamura, Kiana E.,Martin, Daryl J.,Morris, Parker T.,Smith, Haley M.
supporting information, p. 486 - 496 (2022/03/02)
Alkenes are used ubiquitously as starting materials and synthetic targets in all areas of chemistry. Controlling their geometry and position along a chain is vital to their reactivity and properties yet remains challenging. Alkene isomerization is an atom-economical process to synthesize targeted alkenes, and selectivity can be controlled using transition metal catalysts. The development of mild, selective isomerization reactivity has enabled efficient tandem catalytic systems for the remote functionalization of alkenes, a process in which a starting alkene is isomerized to a new position prior to the functionalization step. The key challenges in developing isomerization catalysts for remote functionalization applications are (i) a lack of modularity in the catalyst structure and (ii) the requirement of nonmodular and/or harsh additives during catalyst activation. We address both challenges with a modular (NHC)Ni(0)/silane catalytic system (NHC, N-heterocyclic carbene), demonstrating the use of triaryl silanes and readily accessible (NHC)Ni(0) complexes to form the proposed active (NHC)(silyl)Ni-H species in situ. We show that modification of the steric and electronic nature of the catalyst via modification of the ancillary ligand and silane partner, respectively, is easily achieved, creating a uniquely versatile catalytic system that is effective for the formation of internal alkenes with high yield and selectivity for the E-alkene. The use of silanes as mild activators enables isomerization of substrates with a variety of functional groups, including acid-labile groups. The broad substrate scope, enabled by catalyst design, makes this catalytic system a strong candidate for use in tandem catalytic applications. Preliminary mechanistic studies support a Ni-H insertion/elimination pathway.
METHOD FOR PRODUCING ARENE COMPOUNDS AND ARENE COMPOUNDS PRODUCED BY THE SAME
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Paragraph 0033, (2021/06/26)
Provided is a method for producing (alkyl)arene compounds represented by Formulae 3-1, 3-2, and 3-3 by the Friedel-Crafts alkylation reaction of alkyl halide compounds and arene compounds using organic phosphine compounds as a catalyst.
Direct oxidative isoperfluoropropylation of terminal alkenes: Via hexafluoropropylene (HFP) and silver fluoride
Wang, Xiaojun,Wu, Yongming
supporting information, p. 1877 - 1880 (2018/02/23)
A copper-mediated oxidative isoperfluoropropylation of unactivated terminal alkenes with commercially available hexafluoropropylene (HFP) has been developed. With operational simplicity of the procedure and broad substrate applicability, this strategy pro
Palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane: Synthesis of homoallylic boronic esters
Li, Chunsheng,Li, Meng,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 66 - 69 (2017/12/27)
A palladium-catalyzed oxidative allylation of bis[(pinacolato)boryl]methane to afford the corresponding homoallylic organoboronic esters with moderate to excellent yields is reported. This novel transformation provides an efficient strategy for the construction of homoallylic organoboronic esters in one step with a broad substrate scope. It is proposed that the palladium-catalyzed oxidative allylic C-H bond activation process may be involved in the catalytic cycle.
Cross-Coupling Reactions of Aryldiazonium Salts with Allylsilanes under Merged Gold/Visible-Light Photoredox Catalysis
Akram, Manjur O.,Mali, Pramod S.,Patil, Nitin T.
supporting information, p. 3075 - 3078 (2017/06/23)
A method for the cross-coupling reactions of aryldiazonium salts with trialkylallylsilanes via merged gold/photoredox catalysis is described. The reaction is proposed to proceed through a photoredox-promoted generation of an electrophilic arylgold(III) intermediate that undergoes transmetalation with allyltrimethylsilane to form allylarenes.
Stereospecific Deoxygenation of Aliphatic Epoxides to Alkenes under Rhenium Catalysis
Nakagiri, Takuya,Murai, Masahito,Takai, Kazuhiko
supporting information, p. 3346 - 3349 (2015/07/15)
The combination of a catalytic amount of Re2O7 and triphenyl phosphite as a reductant is effective for the deoxygenation of unactivated aliphatic epoxides to alkenes. The reaction proceeds stereospecifically with variously substituted epoxides under neutral conditions and is compatible with various functional groups. Protection and deprotection of a double bond functionality using an epoxide are shown as an example of the current rhenium-catalyzed deoxygenation protocol. The effect of reductants for the stereoselectivity has also been studied, indicating that the use of electron-deficient phosphines or phosphites is the key for the stereospecific deoxygenation. (Chemical Equation Presented).
Copper(I) 2-hydroxyethoxide-promoted cross-coupling of aryl- and alkenyldimethylsilanes with organic halides
Takeda, Takeshi,Obata, Ryosuke,Muramatsu, Daisuke,Takeda, Yuichiro,Tsubouchi, Akira
supporting information, p. 15156 - 15158 (2014/12/11)
Fluoride-free cross-coupling of aryl- and alkenyldimethylsilanes with organic halides proceeded in the presence of monocopper(I) alkoxide of ethylene glycol.
A facile and convenient sequential homobimetallic catalytic approach towards β-methylstyrenes. A one-pot Stille cross-coupling/isomerization strategy
Simonetti, Sebastian O.,Larghi, Enrique L.,Kaufman, Teodoro S.
, p. 3735 - 3743 (2014/06/09)
An efficient one-pot synthetic approach towards β-methylstyrenes is reported. The transformation, based on sequential homobimetallic catalysis, involves a Stille cross-coupling reaction between aryl halides and allyltributylstannane, followed by an in situ palladium-catalyzed conjugative isomerization. The reaction was optimized, and the best results were obtained with 10 mol% Pd(PPh3)2Cl2, 8.0 equiv. LiCl, and 0.5 equiv. PPh3 in diglyme at 130 °C for 12 h. It was demonstrated that the reaction tolerates a wide variety of functional groups. This journal is the Partner Organisations 2014.
Palladium nanoparticles in glycerol: A versatile catalytic system for C-X bond formation and hydrogenation processes
Chahdoura, Faouzi,Pradel, Christian,Gomez, Montserrat
supporting information, p. 3648 - 3660 (2014/01/06)
Palladium nanoparticles stabilised by tris(3-sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C-X bond formation processes (X=C, N, P, S) and C-C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as-prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular- and surface-like behaviour), has allowed attractive applications in one-pot multi-step transformations catalysed by palladium, such as C-C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor. Copyright
