796-30-5Relevant articles and documents
Phenylnaphthalenes: Sublimation equilibrium, conjugation, and aromatic interactions
Lima, Carlos F. R. A. C.,Rocha, Marisa A. A.,Schroeder, Bernd,Gomes, Ligia R.,Low, John N.,Santos, Luis M. N. B. F.
, p. 3557 - 3570 (2012)
In this work, the interplay between structure and energetics in some representative phenylnaphthalenes is discussed from an experimental and theoretical perspective. For the compounds studied, the standard molar enthalpies, entropies and Gibbs energies of
Experimental and Computational Studies towards Chemoselective C?F over C?Cl Functionalisation: Reversible Oxidative Addition is the Key
Jacobs, Emily,Keaveney, Sinead T.
, p. 637 - 645 (2020/12/07)
Catalytic cross-coupling is a valuable tool for forming new carbon-carbon and carbon-heteroatom bonds, allowing access to a variety of structurally diverse compounds. However, for this methodology to reach its full potential, precise control over all competing cross-coupling sites in poly-functionalised building blocks is required. Carbon-fluorine bonds are one of the most stable bonds in organic chemistry, with oxidative addition at C?F being much more difficult than at other C-halide bonds. As such, the development of methods to chemoselectively functionalise the C?F position in poly-halogenated arenes would be very challenging if selectivity was to be induced at the oxidative addition step. However, metal-halide complexes exhibit different trends in reactivity to the parent haloarenes, with metal-fluoride complexes known to be very reactive towards transmetalation. In this current work we sought to exploit the divergent reactivity of Ni?Cl and Ni?F intermediates to develop a chemoselective C?F functionalisation protocol, where selectivity is controlled by the transmetalation step. Our experimental studies highlight that such an approach is feasible, with a number of nickel catalysts shown to facilitate Hiyama cross-coupling of 1-fluoronapthalene under base free conditions, while no cross-coupling with 1-chloronapthalene occurred. Computational and experimental studies revealed the importance of reversible C?Cl oxidative addition for the development of selective C?F functionalisation, with ligand effects on the potential for reversibility also presented.
Group 4 Diarylmetallocenes as Bespoke Aryne Precursors for Titanium-Catalyzed [2 + 2 + 2] Cycloaddition of Arynes and Alkynes
Reiner, Benjamin R.,Tonks, Ian A.
supporting information, p. 10508 - 10515 (2019/09/13)
Despite the ubiquity of reports describing titanium (Ti)-catalyzed [2 + 2 + 2] cyclotrimerization of alkynes, the incorporation of arynes into this potent manifold has never been reported. The in situ generation of arynes often requires fluoride, which instead will react with the highly fluorophilic Ti center, suppressing productive catalysis. Herein, we describe the use of group 4 diarylmetallocenes, CpR2MAr2 (CpR = C5H5, C5Me5; M = Ti, Zr), as aryne precursors for the Ti-catalyzed synthesis of substituted naphthalenes via coupling with 2 equiv of an alkyne. Fair-to-good yields of the desired naphthalene products could be obtained with 1% catalyst loadings, which is roughly an order of magnitude lower than similar reactions catalyzed by palladium or nickel. Additionally, naphthalenes find broad applications in the electronics, photovoltaics, and pharmaceutical industries, urging the discovery of more economic syntheses. These results indicate that aryne transfer from a CpR2M(?2-aryne) complex to another metal is a viable route for the introduction of aryne fragments into organometallic catalytic processes.
