25486-89-9Relevant articles and documents
Annulative π-Extension of Unactivated Benzene Derivatives through Nondirected C-H Arylation
Lee, Jae Bin,Jeon, Min Ho,Seo, Jeong Kon,Von Helden, Gert,Rohde, Jan-Uwe,Zhao, Bum Suk,Seo, Jongcheol,Hong, Sung You
supporting information, p. 7004 - 7008 (2019/09/07)
Annulative π-extension chemistry provides a concise synthetic route to polycyclic arenes. Herein, we disclose a nondirected annulation approach of unactivated simple arenes. The palladium-catalyzed 2-fold C-H arylation event facilitates tandem C-C linkage relays to furnish fully benzenoid triphenylene frameworks using cyclic diaryliodonium salts. The inseparable regioisomeric mixture of 1- and 2-methyltriphenylenes is identified by the combined analysis of ion mobility-mass spectrometry, gas-phase infrared spectroscopy, and molecular simulation studies.
Photochemical cycloaromatization reactions of ortho-dialkynylarenes: A new class of DNA photocleaving agents
Funk,Young,Williams,Flanagan,Cecil
, p. 3291 - 3292 (2007/10/03)
We are intrigued by the possibility of consolidating the functional elements of the enediyne anticancer antibiotics, thereby simplifying the task of synthesizing potential chemotherapeutic agents which operate by DNA cleavage pathways. Thus, it was envisaged that certain polycyclic ortho-dialkynylarenes would intercalate into DNA and, moreover, the planar π systems might be further exploited by facilitating photochemical, as opposed to thermal, cycloaromatization/cleavage reactions. We report herein on the viability of this photochemical transformation and the resultant new class of DNA photocleaving agents, whose binding and photoactive domains are consolidated, and which generate two reactive sites for subsequent ribose hydrogen atom abstraction(s).
Regioselective Catalytic Hydrogenation of Polycyclic Aromatic Hydrocarbons under Mild Conditions
Fu, Peter P.,Lee, Hong M.,Harvey, Ronald G.
, p. 2797 - 2803 (2007/10/02)
Hydrogenation of polynuclear hydrocarbons over a palladium catalyst at low pressure and ambient temperature affords regiospecifically the corresponding K-region dihydroarenes, while analogous reactions over a platinum catalyst take place regioselectively on terminal rings to provide the related tetrahydroarenes.Hydrogenation over palladium of phenanthrene, benzanthracene, 7,12-dimethylbenzanthracene, benzpyrene, 3-methylcholanthrene, dibenzanthracene, and chrysene gave 9,10-dihydrophenanthrene, 5,6-dihydrobenzanthracene, 5,6-dihydro-7,12-dimethylbenzanthracene, 4,5-dihydrobenzopyrene, 11,12-dihydro-3-methylcholanthrene, 5,6-dihydrodibenzanthracene, and 5,6-dihydrochrysene, respectively (Table I).Hydrogenation over platinum of benzanthracene, 7-methylbenzanthracene, 12-methylbenzanthracene, 7,12-dimethylbenzanthracene, benzopyrene, chrysene, dibenzanthracene, 5,6-dihydrobenzanthracene, 5,6-dihydro-7,12-dimethylbenzanthracene, and 4,5-dihydrobenzopyrene furnished the corresponding terminal ring tetrahydroarenes (Table II).Partial hydrogenation beyond the dihydro stage in the presence of palladium was exhibited only by hydrocarbons with more than one K region.In these cases, the second stage of hydrogen addition was generally slower than the first, so that the extent of reaction was readily controllable.Hydrogenation was blocked by alkyl substitution in an otherwise susceptible ring, and regioselectivity was diminished or abolished by increased hydrogen pressure, prolonged reaction, or acidity.The mechanism of reaction over palladium is proposed to involve concerted hydrogen addition to the K region, the region of minimum bond delocalization energy, preceded by localized ? and/or ? complexes.Evidence is presented that hydrogenations over platinum do not involve initial addition to the K region followed by isomerization into the terminal ring.Instead, these reactions are suggested to involve addition of 2 mol of hydrogen via an intermediate ? complex to the terminal ring which affords the most thermodynamically favored tetrahydroarene product, i.e., that which requires the minimum amount of energy for its formation.
