2381-19-3Relevant academic research and scientific papers
Air-Driven Potassium Iodide-Mediated Oxidative Photocyclization of Stilbene Derivatives
Matsushima, Tomoya,Kobayashi, Sayaka,Watanabe, Soichiro
, p. 7799 - 7806 (2016/09/09)
A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated oxidative photocyclization reactions, this new method requires shorter reaction times and affords cyclized products in yields of 45-97%. This reaction proceeds with a catalytic amount of potassium iodide and works in an air-driven manner without the addition of an external scavenger. The radical-mediated oxidative photocyclization of stilbene derivatives using TEMPO was also investigated.
Domino Friedel-crafts-type cyclizations of difluoroalkenes promoted by the α-cation-stabilizing effect of fluorine: An efficient method for synthesizing angular PAHs
Fuchibe, Kohei,Jyono, Hideharu,Fujiwara, Masaki,Kudo, Takao,Yokota, Misaki,Ichikawa, Junji
, p. 12175 - 12185 (2011/12/01)
In order to synthesize polycyclic aromatic hydrocarbons with nonlinear arrangements (angular PAHs), acid-promoted domino cyclizations of 1,1-difluoroalk-1-enes and 1,1-difluoroalka-1,3-dienes were studied. 1,1-Difluoroalkenes, each bearing two aryl substituents, were regioselectively protonated with FSO3H·SbF5 to generate fluorine-stabilized carbocations, which readily underwent domino Friedel-Crafts-type cyclizations to give carbocycles based on 6/n/m/6 ring systems (n,m=5-7) in good to high yields. Protonation of 1,1-difluoroalka-1,3- dienes took place at their electron-rich methylene (CH2) carbon atoms in the presence of milder acids such as camphorsulfonic acid and trifluoromethanesulfonic acid. Domino cyclizations of the resulting fluorine-stabilized allylic carbocations afford carbocycles based on 6/6/6/6 or 6/6/5/6 ring systems in high yields.
Efficient helicene synthesis: Friedel-crafts-type cyclization of 1,1-difluoro-1-alkenes
Ichikawa, Junji,Yokota, Misaki,Kudo, Takao,Umezaki, Satoshi
supporting information; experimental part, p. 4870 - 4873 (2009/02/08)
(Chemical Equation Presented) The unique properties of fluorine substituents, leaving groups that also stabilize an a carbocation, are exploited in a high-yielding synthesis of substituted [4]- to [6]helicenes in three or four steps from commercially available compounds: Two fused benzene rings are constructed in the title reaction of readily prepared 1,1-difluoro-1-alkenes containing two aryl groups followed by dehydrogenation (see scheme).
SYNTHESE PHOTOCHIMIQUE D'HYDROCARBURES POLYCYCLIQUES AROMATIQUES ET ETUDE EN RMN-1H DES PROTONS DE BAIE. EFFECTS DE SOLVANT SPECIFIQUES ET EFFECTS NUCLEAIRES OVERHAUSER.
Brison, Jean,Bakker, Claude de,Defay, Nicole,Geerts-Evrard, France,Marchant, Marie-Jeanne,Martin, Richard H.
, p. 901 - 912 (2007/10/02)
"Photochemical synthesis of polycyclic aromatic hydrocarbons and NMR-1H study of bay protons.Specific solvent effects and nuclear Overhauser effects".Dinaphthoanthracene (4a),9-bromo-dinaphthoanthracene (4b), 9-methyldinaphthoanthracene (4c), benzonaphthochrysene (7), benzonaphthoanthracene (3), naphthochrysene (9) and dibenzonaphthochrysene (12) have been synthesized by the photocyclodehydrogenation of 1,2-diarylethylenes (5,8) and bis (arylvinyl)arenes (6,10).The NMR study has been mainly focused on the bay protons involved in specific solvent effects Table 4) and nuclear Overhauser effects (Table 5).
