The rate of ipso electrophilic substitution in aryltrimethylsilanes is so rapid that it is possible to obtain regiospecific electrophilic halogenations in many aromatic compound^.^^^ Indeed, it is possible to selectively obtain the ortho-and para-brominated derivatives of aromatic compounds containing deactivating, meta-directing substituents such as benzoic acids. 5 However, highly activated aromatic rings are so strongly ortho and para directing that ipso ...
[Bennett, Christopher J.; Caldwell, Stuart T.; McPhail, Donald B.; Morrice, Philip C.; Duthie, Garry G.; Hartley, Richard C. Bioorganic and Medicinal Chemistry, 2004 , vol. 12, # 9 p. 2079 - 2098]