5153-40-2Relevant articles and documents
Keefer,Andrews
, p. 3637,3640 (1956)
Strategic Application and Transformation of ortho-Disubstituted Phenyl and Cyclopropyl Ketones to Expand the Scope of Hydrogen Borrowing Catalysis
Frost, James R.,Cheong, Choon Boon,Akhtar, Wasim M.,Caputo, Dimitri F. J.,Stevenson, Neil G.,Donohoe, Timothy J.
supporting information, p. 15664 - 15667 (2016/01/09)
The application of an iridium-catalyzed hydrogen borrowing process to enable the formation of α-branched ketones with higher alcohols is described. In order to facilitate this reaction, ortho-disubstituted phenyl and cyclopropyl ketones were recognized as crucial structural motifs for C-C bond formation. Having optimized the key catalysis step, the ortho-disubstituted phenyl products could be further manipulated by a retro-Friedel-Crafts acylation reaction to produce synthetically useful carboxylic acid derivatives. In contrast, the cyclopropyl ketones underwent homoconjugate addition with several nucleophiles to provide further functionalized branched ketone products.
Role of substitution on the photophysical properties of 5,5′-diaryl-2,2′-bipyridine (bpy*) in [Ir(ppy) 2(bpy*)]PF6 complexes: A combined experimental and theoretical study
Ladouceur, Sebastien,Fortin, Daniel,Zysman-Colman, Eli
scheme or table, p. 5625 - 5641 (2010/08/04)
The synthesis of a family of 4′-functionalized 5,5′-diaryl-2, 2′-bipyridines (bpy*; 6a-6g) is reported. These ligands were reacted with the dimer [(ppy)2IrCl]2 (ppyH = 2-phenylpyridine) and afforded, after subsequent counterion exchange, a new series of luminescent cationic heteroleptic iridium(III) complexes, [(ppy)2Ir(bpy*)] PF6 (8a-8g). These complexes were characterized by electrochemical and spectroscopic methods. The crystal structures of two of these complexes (8a and 8g) are reported. All of the complexes except for 8c and 8f exhibit intense and long-lived emission in both 2-MeTHF and ACN at 77 K and room temperature. The origin of this emission has been assigned by computational modeling to be an admixture of ligand-to-ligand charge-transfer [3LLCT; π(ppy) → π*(bpy*)] and metal-to-ligand charge-transfer [ 3MLCT; dπ(Ir) → π*(bpy*)] excited states that are primarily composed of the former. The luminescent properties for 8a-8c are dependent upon the functionalization at the 4′ position of the aryl substituents affixed to the diimine ligand, while those for 8d-8g are essentially independent because of an electronic decoupling of the aryls and bpy due to the substitution of o,o-dimethyl groups on the aryls, causing a near 90° angle between the aryl and bipyridyl moieties. A combined density functional theory (DFT)/time-dependent DFT study was conducted in order to understand the origin of the transitions in the absorption and emission spectra and to predict accurately emission energies for these complexes.
Positional Reactivity of Acylpolymethylbenzenes in Electrophilic Substitution
Matsuura, Kazunori,Kimura, Yasuo,Takahashi, Hisakazu,Morita, Toshio,Takahashi, Ichiro,et al.
, p. 757 - 765 (2007/10/02)
Friedel-Crafts acylation, bromination, deuteration, and nitration of acetylpentamethylbenzene (APMB), 1-acetyl-2,3,4,6-tetramethylbenzene (ATMB), and 1-benzoyl-2,3,4,6-tetramethylbenzene (BTMB) and the resulting product distribution were investigated.Friedel-Crafts acylation, bromination, and deuteration of APMB and Friedel-Crafts acylation of ATMB gave deacetylation-substitution products.On the other hand, bromination and deuteration of ATMB (or BTMB) and Friedel-Crafts acylation of BTMB gave 5-substituted products.In both cases, the positional reactivities were in accordance with the relative ?-complex stability.Conversely, except for Friedel-Crafts-type nitration, the positional reactivities in the nitration of these substrates were strikingly different from those of the above three reactions.Thus, side-chain functionalization at the 6-methyl group occurred in nitration with fuming nitric acid, depending on the solvents in use.The NMDO calculations and the reaction of APMB with single-electron transfer reagents such as tetranitromethane-hν or cerium(IV) ammonium nitrate suggest that the product distribution in nitration can be explained in terms of a single-electron transfer mechanism.
