Domino Friedel-Crafts-Type Cyclizations of Difluoroalkenes Promoted by the α-Cation-Stabilizing Effect of Fluorine: An Efficient Method for Synthesizing Angular PAHs
作者:Kohei Fuchibe、Hideharu Jyono、Masaki Fujiwara、Takao Kudo、Misaki Yokota、Junji Ichikawa
DOI:10.1002/chem.201100618
日期:2011.10.17
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
为了合成具有非线性排列的多环芳烃(角PAHs),研究了1,1-二氟烷-1-烯和1,1-二氟烷基-1,3-二烯的酸促进的多米诺环化反应。1,1- Difluoroalkenes,每个轴承2芳基取代基,分别与区域选择性FSO质子化3 H⋅SbF 5,以产生氟稳定化的碳阳离子,它容易后行骨牌的Friedel-Crafts型环化反应根据6 /,得到碳环ñ /米/ 6环系统(n,m = 5–7),产量高至高。1,1-二氟烷基-1,3-二烯的质子化在其富电子的亚甲基(CH 2)碳原子存在于较弱的酸(如樟脑磺酸和三氟甲磺酸)中。所得的氟稳定的烯丙基碳正离子的多米诺环化反应以高收率提供了基于6/6/6/6或6/6/5/6环体系的碳环。