51136-87-9Relevant articles and documents
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
experimental part, 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.
Friedel-Crafts-type cyclization of 2,2-difluorovinyl ketones via α-fluorocarbocations and its application in domino cyclizations
Ichikawa, Junji,Kaneko, Mikio,Yokota, Misaki,Itonaga, Masaaki,Yokoyama, Takaharu
, p. 3167 - 3170 (2007/10/03)
2,2-Difluorovinyl ketones bearing an aryl group undergo Friedel-Crafts-type cyclization via carbocations stabilized by α-fluorines on treatment with a trimethylsilylating agent [Me3SiOTf or Me3SlB(OTf) 4]. The reaction aff