Domino Friedel-Crafts-type cyclizations of difluoroalkenes promoted by the α-cation-stabilizing effect of fluorine: an efficient method for synthesizing angular PAHs
Fuchibe, K; Jyono, H; Fujiwara, M; Kudo, T; Yokota, M; Ichikawa, J
| HERO ID | 5415212 |
|---|---|
| In Press | No |
| Year | 2011 |
| Title | Domino Friedel-Crafts-type cyclizations of difluoroalkenes promoted by the α-cation-stabilizing effect of fluorine: an efficient method for synthesizing angular PAHs |
| Authors | Fuchibe, K; Jyono, H; Fujiwara, M; Kudo, T; Yokota, M; Ichikawa, J |
| Journal | Chemistry: A European Journal |
| Volume | 17 |
| Issue | 43 |
| Page Numbers | 12175-12185 |
| Abstract | 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 FSO(3)H⋅SbF(5) 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 (CH(2)) 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. |
| Doi | 10.1002/chem.201100618 |
| Pmid | 21922570 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |