- C-H and C-F bond activation reactions of pentafluorostyrene at rhodium complexes
-
The rhodium(i) complexes [Rh(Bpin)(PEt3)3] (1), [Rh(H)(PEt3)3] (5) and [Rh(Me)(PEt3)3] (14) were employed in reactions with pentafluorostyrene affording coordination of the olefin and C-F o
- Xu, Conghui,Talavera, Maria,Sander, Stefan,Braun, Thomas
-
-
Read Online
- HOMOGENEOUS CATALYSIS OF MIXED-METAL SYSTEMS. HIGHLY REGIOSELECTIVE HYDROFORMYLATION-AMIDOCARBONYLATION OF A FLUORO OLEFIN CATALYZED BY Co-Rh MIXED-METAL SYSTEMS. OBSERVATION OF CoRh(CO)7 CATALYSIS.
-
The hydroformylation-amidocarbonylation of a fluoro olefin, C//6F//5CH equals CH//2, catalyzed by Co//2(CO)//8-rhodium carbonyl systems proceeds with excellent regioselectivity. The process includes a unique Co-Rh mixed-metal complex, CoRh(CO)//7, as an a
- Ojima,Okabe,Kato,Kwon,Horvath
-
-
Read Online
- Hydrogenation of Alkenes Catalyzed by a Non-pincer Mn Complex
-
Hydrogenation of substituted styrenes and unactivated aliphatic alkenes by molecular hydrogen has been achieved using a Mn catalyst with a non-pincer, picolylphosphine ligand. This is the second reported example of alkene hydrogenation catalyzed by a Mn complex. Mechanistic studies showed that a Mn hydride formed by H2 activation in the presence of a base is the catalytically active species. Based on experimental and DFT studies, H2 splitting is proposed to occur via a metal-ligand cooperative pathway involving deprotonation of the CH2 arm of the ligand, leading to pyridine dearomatization.
- Rahaman, S. M. Wahidur,Pandey, Dilip K.,Rivada-Wheelaghan, Orestes,Dubey, Abhishek,Fayzullin, Robert R.,Khusnutdinova, Julia R.
-
p. 5912 - 5918
(2020/10/30)
-
- +: A Masked Potent Boron Lewis Acid
-
The chemistry of the boron cation has been revitalized in the past decade due to its newfound application in stoichiometric and catalytic organic reactions. To extend the frontier of boron cation catalysis, we came to discover that a mesityl-substituted η5-Cp*-coordinated boron cation could serve as a powerful Lewis acid for organic catalytic transformations. The boron cation [Cp*B-Mes][B(C6F5)4] ([1][B(C6F5)4]) stabilized in a boronium-like electronic structure binds to Et3PO readily and displays an acceptor number exceeding that of B(C6F5)3 on the Gutmann-Beckett acidity scale. The steric and electronic stabilization exerted by the electron-donating Cp? renders the highly Lewis acidic boron cation an easy-to-handle catalyst for hydrodeoxygenation of aryl ketones at ambient temperature. The exceptional catalytic performance of [1]+ implies that the incorporation of a coordinatively flexible substituent at boron is critical in bringing catalytic activity and stability to boron cation catalysts.
- Tseng, Hsi-Ching,Shen, Chao-Tang,Matsumoto, Kentaro,Shih, Ding-Nan,Liu, Yi-Hung,Peng, Shie-Ming,Yamaguchi, Shigehiro,Lin, Ya-Fan,Chiu, Ching-Wen
-
supporting information
p. 4516 - 4521
(2019/11/14)
-
- Heterogeneous Catalytic Hydroarylation of Olefins at a Nanoscopic Aluminum Chlorofluoride
-
We report on hydroarylation reactions of arenes with olefins under very mild conditions catalyzed heterogeneously by aluminum chlorofluoride (ACF; AlClxF3?x, x≈0.05–0.25). The reactions of benzene and toluene with ethylene or propylene proceed with high conversions to afford various alkylated arenes. For cyclohexene and 1-hexene, the reactions require higher temperatures and the conversions are lower. ACF also catalyzes the hydroarylation of 1,3,5-trifluorobenzene and pentafluorobenzene with ethylene and propylene. The alkylations of arenes with non-fluorinated olefins resemble typical Friedel–Crafts chemistry to give rise to Markovnikov regioselectivity. The reaction of CF3CH=CH2 with benzene proceeds with anti-Markovnikov regioselectivity to give the fluorinated olefin PhCHCH=CF2 and the alkylation product PhCH2CH2CF3 as products of C?F and C?H activation.
- Calvo, Beatriz,Wuttke, Jan,Braun, Thomas,Kemnitz, Erhard
-
p. 1945 - 1950
(2016/07/06)
-
- Phosphido- and Amidozirconocene Cation-Based Frustrated Lewis Pair Chemistry
-
Methyl abstraction from neutral [Cp2ZrMe(ERR)] complexes 1 (E = N, P; R, R'; = alkyl, aryl) with either B(C6F5)3 or [Ph3C][B(C6F5)4] results in the formation of [Cp2Zr(ERR′)][X] complexes 2 (X- = MeB(C6F5)3-, B(C6F5)4-). The X-ray structure of amido complexes [Cp2Zr(NPh2)][MeB(C6F5)3] (2d) and [Cp2Zr(NtBuAr)][B(C6F5)4] (2e′, Ar = 3,5-C6H3(CH3)2) is reported, showing a sterically dependent Zr/N' interaction. Complexes 2 catalyze the hydrogenation of electron-rich olefins and alkynes under mild conditions (room temperature, 1.5 bar H2). Complex 2e binds CO2, giving [Cp2Zr(CO2)(NtBuAr)]2[MeB(C6F5)3]2 (3e). Amido complex 2d reacts with benzaldehyde yielding [Cp2Zr(OCH2Ph)((OC)PhNPh2)][MeB(C6F5)3] (7d). Phosphido complex [Cp2Zr(PCy2)][MeB(C6F5)3] (2a) reacts with diphenylacetylene to yield frustrated Lewis pair [Cp2Zr(PhCCPh)(PCy2)][MeB(C6F5)3] (8a) which further reacts with a range of carbonyl substrates.
- Normand, Adrien T.,Daniliuc, Constantin G.,Wibbeling, Birgit,Kehr, Gerald,Le Gendre, Pierre,Erker, Gerhard
-
supporting information
p. 10796 - 10808
(2015/09/28)
-
- Transition-metal-free synthesis of fluorinated arenes from perfluorinated arenes coupled with grignard reagents
-
A simple method to obtain organofluorine compounds from perfluorinated arenes coupled with Grignard reagents in the absence of a transition-metal catalyst was reported. In particular, the perfluorinated arenes could react not only with aryl Grignard reagents but also with alkyl Grignard reagents in moderate to good yields.
- Sun, Yunqiang,Sun, Hongjian,Jia, Jiong,Du, Aiqin,Li, Xiaoyan
-
supporting information
p. 1079 - 1081
(2014/03/21)
-
- C6F5XeY Molecules (Y = F and Cl): New synthetic approaches. first structural proof of the organoxenon halide molecule C 6F5XeF
-
The arylxenonium salt [C6F5Xe][BF4] reacts with different sources of nucleophiles, Y (naked fluoride, [N(CH 3)4]F, the silanes, (CH3)3SiCl and (C2H5)3SiH, and the cadmiumorganyl, Cd(C 6F5)2), in coordinating solvents (C 2H5CN, CH3CN, CD3CN). While the products C6F5XeF, C6F5XeCl, and (C6F5)2Xe are well defined molecules, in reactions with (C2H5)3SiH only decomposition products presumably derived from 6F5XeH6F5XeC2H56F5XeF are discussed.
- Bilir, Vural,Frohn, Hermann-Josef
-
p. 505 - 512
(2013/09/23)
-
- Rhodium(I) acetylacetonato complexes containing phosphinoalkynes as catalysts for the hydroboration of vinylarenes
-
Three novel rhodium(I) acetylacetonato (acac) complexes bearing phosphinoalkynes (Ph2PC≡C-t-Bu, Ph2PC≡ CPPh2, and Ph2PC≡CC≡CPPh2) have been prepared and characterized fully. Addition of B2cat3 (cat = 1,2-O2C6H4) to Rh(acac)(Ph 2PC≡C-t-Bu)2 (1a) led to zwitterionic Rh(η6-catBcat)(Ph2PC≡C-t-Bu)2 (2a), the first example of this type of compound to contain monodentate phosphine ligands. All new rhodium complexes have been investigated for their ability to catalyse the hydroboration of vinylarenes.
- Vogels, Christopher M.,Decken, Andreas,Westcott, Stephen A.
-
p. 146 - 153
(2007/10/03)
-
- Hydroformylation of Fluoro Olefins, RfCH=CH2, Catalyzed by Group VIII Transition-Metal Catalysts. Crucial Factors for Extremely High Regioselectivity
-
Hydroformylations of fluoro olefins, trifluoroprop-1-ene (TFP), pentafluorobut-1-ene (PFB), heptafluoropent-1-ene (HPFP), heptadecafluorodec-1-ene (HPDFD), vinyl fluoride (VF), pentafluorostyrene (PFS), and allylpentafluorobenzene (4a), promoted by transition-metal catalysts were studied.Remarkable dependency of the regioselectivity of the reaction on the catalyst metal species (Co, Pt, Ru, and Rh) was found in the reactions of TFP and PFS; e.g., n-aldehyde was obtained with >93percent selectivity by a cobalt catalyst whereas iso-aldehyde was obtained with >96percent selectivity by a rhodium catalyst for the reaction of TFP.On the contrary, the reaction of VF gave 2-fluoropropanal (2-FPA) exclusively, regardless of the metal catalyst species.The effects of temperature and carbon monoxide pressure on the regioselectivity were investigated.Possible mechanisms for the uniquely regioselective hydroformylations are discussed on the basis of the results obtained, and a mechanism that involves an initial formation of isoalkyl-metal species followed by isomerization to n-alkyl-metal species and/or followed by carbon monoxide insertion to form isoacyl-metal intermediate was proposed to be the one operating in these reactions.
- Ojima, Iwao,Kato, Koji,Okabe, Masami,Fuchikami, Takamasa
-
p. 7714 - 7720
(2007/10/02)
-
- THE REACTIONS OF HYDROSILANES WITH TRIFLUOROPROPENE AND PENTAFLUOROSTYRENE CATALYZED BY RUTHENIUM, RHODIUM AND PALLADIUM COMPLEXES
-
The reactions of hydrosilanes with trifluoropropene (TFP) and pentafluorostyrene (PFS) catalyzed by Ru3(CO)12 or RhCl(PPh3)3 give β-Rf-vinylsilane (1) and/or β-Rf-ethylsilane (2) (Rf=perfluorocarbon group).The 1/2 ratio is highly dependent on the nature of hydrosilane used.The ruthenium catalyst favors the formation of 1 compared with the rhodium catalyst.Neither α-Rf-vinylsilane nor α-Rf-ethylsilane was formed at all.Possible mechanisms which can accommodate characteristic features of these reactions are discussed.The hydrosilylation of TFP with dichloromethylsilane catalyzed by PdCl2(PhCN)2/2PPh3 gives the α-adduct (9a) exclusively, and this is transformed to the corresponding dialkoxysilanes, silane diol, oligosilane diols and cyclic oligosiloxanes.
- Ojima, Iwao,Fuchikami, Takamasa,Yatabe, Momoko
-
p. 335 - 346
(2007/10/02)
-