19303-32-3Relevant academic research and scientific papers
Organopromoted Direct Synthesis of 1,1-Diphenyl-3-arylindanes via Formal [3+2] Cycloadditions of Triphenylcarbenium Tetrafluoroborate with Styrenes
Surapanich, Nakin,Chaisuwan, Patcharin,Kuhakarn, Chutima,Reutrakul, Vichai
, p. 2689 - 2694 (2016)
A formal [3+2] cycloaddition of triphenylcarbenium tetrafluoroborate with structurally different styrene derivatives has been developed. A combination of benzophenone and Et3N is key for promoting a formal [3+2] cycloaddition of triphenylcarbenium tetrafluoroborate with styrenes affording 1,1-diphenyl-3-arylindanes in moderate to good yields. The reaction mechanism of this transformation is also discussed.
Synthesis and Catalytic Activity of Atrane-type Hard and Soft Lewis Superacids with a Silyl, Germyl, or Stannyl Cationic Center
Tanaka, Daiki,Konishi, Akihito,Yasuda, Makoto
, p. 3118 - 3123 (2021)
The synthesis and isolation of atrane-type molecules 1E+ (E=Si, Ge, or Sn) having a cationic group 14 elemental center are reported. The cations 1E+ act as hard and soft Lewis superacids, which readily interact with various hard and soft Lewis basic substrates. The rigid atrane framework stabilizes the localized positive charge on the elemental center and assists the formation of the well-defined highly coordinated states of 1E+. The cations were applied to the hydrodefluorination, Friedel-Crafts reaction, alkyne cyclization, and carbonyl reduction as Lewis acid catalysts. Most notably, [1Si][ClO4] exhibits unique chemoselectivity that depends on a solvent in the competitive reaction of silyl enol ether with a mixture of benzaldehyde dimethyl acetal and benzaldehyde. Our findings indicate the potential of hard and soft Lewis superacids in organic synthesis.
Simple and one-pot protocol for synthesis of indene-spiro-oxindoles involving tandem Prins and Friedel-Crafts reactions
Basavaiah, Deevi,Reddy, Kanumuri Ramesh
, p. 57 - 60 (2007)
(Chemical Equation Presented) A simple and one-pot protocol for the synthesis of indene-spiro-oxindole derivatives via TiCl4-mediated reaction between 1,1-diarylethylenes and isatin derivatives involving construction of two carbon-carbon bonds
Probing steric influences on electrophilic phosphonium cations: A comparison of [(3,5-(CF3)2C6H3)3PF]+ and [(C6F5)3PF]+
Lafortune, James H. W.,Szkop, Kevin M.,Farinha, Farah E.,Johnstone, Timothy C.,Postle, Shawn,Stephan, Douglas W.
, p. 11411 - 11419 (2018)
The electrophilic phosphonium cation (EPC) salt [(3,5-(CF3)2C6H3)3PF][B(C6F5)4] (2) is prepared via oxidation of the precursor phosphine with XeF2 and subse
Alkoxymagnesium iodide complexes
Haiss, Peter,Kuhn, Annette,Kuhn, Norbert,Maichle-Moessmer, Caecilia,Laufer, Stefan,Steimann, Manfred,Zeller, Klaus-Peter
, p. 3284 - 3287 (2011)
The complexes R(Ph)MeCOMg(Et2O)I [1, R = Me (a), Ph (b)] were obtained by the reaction of R(Ph)C=O with MeMgI in diethyl ether in good yields. Crystallisation of 1 from acetonitrile resulted in single crystals of di- and trinuclear complexes I2(μ-OCPhMe2)2Mg(MeCN) 4 (2) and {2[I(MeCN)Mg(μ-OCPh2Me)2Mg(MeCN)I] (3) × [I(MeCN)Mg(μ-OCPh2Me)2Mg(μ-OCPh 2Me)2Mg(MeCN)I] (4) × 2CH2Cl2} in which the metal centres are linked by alkoxy substituents. The thermal decomposition of the complexes 1 was studied by successive detection of the EI mass spectra of diethyl ether, the olefins 5, the tertiary alcohols 6, and the formal olefin dimers 7. The complexes R1(Ph)MeCOMg(Et2O)I [1, R1 = Me (a), Ph (b)] are obtained by the reaction of R 1(Ph)C=O with MeMgI in diethyl ether in good yields. Crystallisation of 1 from acetonitrile results in single crystals of di- and trinuclear complexes (2, 3 and 4) in which the metal centres are linked by alkoxy substituents. The thermal decomposition of the complexes 1 is monitored by mass spectral detection of the decomposition products. Copyright
Metal-free pincer ligand chemistry polycationic phosphonium Lewis acids
Szkop, Kevin M.,Stephan, Douglas W.
, p. 3921 - 3928 (2017)
Oxidation of 2,6-bis(diphenylphosphine)methyl pyridine with MeO3SCF3, yields the dication [2,6-(CH2PMePh2)2C5H3N][CF3SO3]22, while subsequent treatment with two equivalents of [K(THF)n][B(C6F5)4] (n = 1.3-1.5) afforded [2,6-(CH2PMePh2)2C5H3N][B(C6F5)4]23. Analogous treatment using XeF2 afforded 2,6-(CH2PF2Ph2)2C5H3N 4, while subsequent fluoride abstractions afford the corresponding [BF4], [CF3SO3] and [B(C6F5)4] salts, 5-7, respectively. Compound 4 reacts with an excess of MeO3SCF3 to give [2,6-(CH2PF2Ph2)2C5H3N(CH3)][CF3SO3] 8 while subsequent reaction with [Et3Si·2C7H8][B(C6F5)4] gave the related tricationic species, 9. The Lewis acidity of these di- and triphosphonium cations 3, 7 and 9 was examined and their utility as Lewis acid catalysts was assessed in the dimerization of 1,1-diphenylethylene, the hydrodefluorination of 1-fluoroadamantane, and the dehydrocoupling of phenol and silane.
Lewis Superacidic Catecholato Phosphonium Ions: Phosphorus-Ligand Cooperative C-H Bond Activation
Greb, Lutz,Roth, Daniel,Stephan, Douglas W.,Stirn, Judith
supporting information, p. 15845 - 15851 (2021/10/02)
A series of catecholato phosphonium ions, including the first stable bis(catecholato)-substituted derivatives, are isolated and fully characterized. The cations rank among the most potent literature-known Lewis acids on the Gutmann-Beckett and ion affinit
Towards Naked Zinc(II) in the Condensed Phase: A Highly Lewis Acidic ZnII Dication Stabilized by Weakly Coordinating Carborate Anions
Adet, Nicolas,Specklin, David,Gourlaouen, Christophe,Damiens, Thibault,Jacques, Béatrice,Wehmschulte, Rudolf J.,Dagorne, Samuel
, p. 2084 - 2088 (2020/11/30)
The employment of the hexyl-substituted anion [HexCB11Cl11]? allowed the synthesis of a ZnII species, Zn[HexCB11Cl11]2, 3, in which the Zn2+ cation is only weakly coordinated to two carborate counterions and that is soluble in low polarity organic solvents such as bromobenzene. DOSY NMR studies show the facile displacement of at least one of the counterions, and this near nakedness of the cation results in high catalytic activity in the hydrosilylation of 1-hexene and 1-methyl-1cyclohexene. Fluoride ion affinity (FIA) calculations reveal a solution Lewis acidity of 3 (FIA=262.1 kJ mol?1) that is higher than that of the landmark Lewis acid B(C6F5)3 (FIA=220.5 kJ mol?1). This high Lewis acidity leads to a high activity in catalytic CO2 and Ph2CO reduction by Et3SiH and hydrogenation of 1,1-diphenylethylene using 1,4-cyclohexadiene as the hydrogen source. Compound 3 was characterized by multinuclear NMR spectroscopy, mass spectrometry, single crystal X-ray diffraction, and DFT studies.
Nitrenium Salts in Lewis Acid Catalysis
Mehta, Meera,Goicoechea, Jose M.
supporting information, p. 2715 - 2719 (2020/01/24)
Molecular compounds featuring nitrogen atoms are typically regarded as Lewis bases and are extensively employed as donor ligands in coordination chemistry or as nucleophiles in organic chemistry. By contrast, electrophilic nitrogen-containing compounds are much rarer. Nitrenium cations are a new family of nitrogen-based Lewis acids, the reactivity of which remains largely unexplored. In this work, nitrenium ions are explored as catalysts in five organic transformations. These reactions are the first examples of Lewis acid catalysis employing nitrogen as the site of substrate activation. Moreover, these compounds are readily accessed from commercially available reagents and exhibit remarkable stability toward moisture, allowing for benchtop transformations without the need to pretreat solvents.
Bis(perchlorocatecholato)germane: Hard and Soft Lewis Superacid with Unlimited Water Stability
Greb, Lutz,Roth, Daniel,Wadepohl, Hubert
supporting information, p. 20930 - 20934 (2020/09/17)
Previously described Lewis superacids are moisture sensitive and predominantly hard in character—features that severely limit their widespread use in orbital-controlled reactions and under non-inert conditions. Described here are adducts of bis(perchlorocatecholato)germane, the first hard and soft Lewis superacid based on germanium. Remarkably, the synthesis of this compound is performed in water, and the obtained H2O adduct constitutes a strong Br?nsted acid. If applied as an adduct with aprotic donors, it displays excellent activity in a diverse set of Lewis acid catalyzed transformations, covering hydrosilylation, hydrodefluorination, transfer hydrogenation, and carbonyl–olefin metathesis. Given the very straightforward synthetic access from two commercially available precursors, the unlimited water stability and the soft Lewis acidic character, it promotes the transfer of Lewis superacidity into organic synthesis and materials science.
