253185-03-4Relevant articles and documents
Selective, nickel-catalyzed hydrogenolysis of aryl ethers
Sergeev, Alexey G.,Hartwig, John F.
, p. 439 - 443 (2011)
Selective hydrogenolysis of the aromatic carbon-oxygen (C-O) bonds in aryl ethers is an unsolved synthetic problem important for the generation of fuels and chemical feedstocks from biomass and for the liquefaction of coal. Currently, the hydrogenolysis of aromatic C-O bonds requires heterogeneous catalysts that operate at high temperature and pressure and lead to a mixture of products from competing hydrogenolysis of aliphatic C-O bonds and hydrogenation of the arene. Here, we report hydrogenolyses of aromatic C-O bonds in alkyl aryl and diaryl ethers that form exclusively arenes and alcohols. This process is catalyzed by a soluble nickel carbene complex under just 1 bar of hydrogen at temperatures of 80 to 120°C; the relative reactivity of ether substrates scale as Ar-OAr?Ar-OMe>ArCH2-OMe (Ar, Aryl; Me, Methyl). Hydrogenolysis of lignin model compounds highlights the potential of this approach for the conversion of refractory aryl ether biopolymers to hydrocarbons.
Metal-free electrophilic fluorination of alkyl trifluoroborates and boronic acids
Cazorla, Clément,Métay, Estelle,Andrioletti, Bruno,Lemaire, Marc
, p. 3936 - 3938 (2009)
Secondary alkyl trifluoroborates undergo facile electrophilic fluorination under mild conditions to afford the corresponding benzylic fluorinated adducts in excellent yield.
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Winstein,Seubold
, p. 2916 (1947)
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Huston,Krantz
, p. 63,66, 67 (1948)
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STABLE AND CONVENIENT ALKYLTITANIUM REAGENTS FOR ORGANIC SYNTHESIS
Erskine, Gordon J.,Hunter, Brian K.,McCowan, James D.
, p. 1371 - 1374 (1985)
Monocyclopentadienyl titanium alkyls perform similarly to other alkyltitanium reagents in reactions with carbonyl groups while possessing significantly greater thermal stability.
THE "SUPER-BASIC" BUTYLLITHIUM/POTASSIUM TERT-BUTOXIDE MIXTURE AND OTHER LICKOR-REAGENTS
Schlosser, Manfred,Strunk, Sven
, p. 741 - 744 (1984)
The reactivity pattern of the butyllithium/potassium tert-butoxide mixture differs significantly from that of butylpotassium and thus disproves the claimed identity of these two reagents.
Quantum Yields of the Initiation Step and Chain Propagation Turnovers in SRN1 Reactions: Photostimulated Reaction of 1-Iodo-2-methyl-2-phenyl Propane with Carbanions in DMSO
Argueello, Juan E.,Penenory, Alicia B.,Rossi, Roberto A.
, p. 7175 - 7182 (2000)
Neophyl radicals were generated by photoinduced electron transfer (PET) from a suitable donor to the neophyl iodide (1, 1-iodo-2-methyl-2-phenylpropane). The PET reaction of 1 with the enolate anion of cyclohexenone (2) afforded mainly the reduction products tert-butylbenzene (5) and the rearranged isobutylbenzene (6), arising from hydrogen abstraction of the neophyl radical (15) and the rearranged radical 16 intermediates, respectively. The photostimulated reaction of 1 with 2 in the presence of di-tert-butylnitroxide, as a radical trap, afforded adduct 10 in 57% yield. The photoinduced reaction of the enolate anion of acetophenone (3) with 1 gave the substitution products 11 (50%) and 12 (16%), which arise from the coupling of 3 with radicals 15 and 16, respectively. The rate constant obtained for the addition of anion 3 to radical 15 was 1.2 × 105 M-1 s-1, by the use of the rearrangement of this radical as a clock reaction. The anion of nitromethane (4) was almost unreactive at the initiation step, but in the presence of 2 under irradiation, it gave high yields (67%) of the substitution product 13 and only 2% of the rearranged product 14. When the ratio of 4 to 1 was diminished, it was possible to observe both substitution products 13 and 14 in 16% and 6.4% yields, respectively. These last results allowed us to estimate the coupling rate constant of neophyl radicals 15 with anion 4 to be at least of the order of 106 M-1 s-1. Although the overall quantum yield determined (λ = 350 nm) for the studied reactions is below 1, the chain lengths (Φpropagation) for the reaction of 1 with anions 3 and 4 are 127 and 2, respectively.
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Urry,Kharasch
, p. 1438,1440 (1944)
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Berliner,Bondhus
, (1948)
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Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
García Manche?o, Olga,Kuhlmann, Jan H.,Uygur, Mustafa
, p. 1689 - 1694 (2022/03/14)
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)-Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient and selective desilylation of a broad variety of simple and complex arylsilanes under mild conditions.
Nickel-Catalyzed Photodehalogenation of Aryl Bromides
Higginson, Bradley,Sanjosé-Orduna, Jesus,Gu, Yiting,Martin, Ruben
supporting information, p. 1633 - 1636 (2021/04/23)
Herein, we describe a Ni-catalyzed photodehalogenation of aryl bromides under visible-light irradiation that utilizes tetrahydrofuran as hydrogen source. The protocol obviates the need for exogeneous amine reductants or photocatalysts and is characterized by its simplicity and broad scope, including challenging substrate combinations.
