Activation of Electrophilic Sites by Adjacent Cationic Groups

Superelectrophiles and the Effects of Trifluoromethyl Substituents

“…The −CF 3 group primarily activates electrophilic sites by inductive electron-withdrawing effects. Similar electrophilic activation has been observed from cationic functional groups and structures . Depending on the cationic group, very strong electron-withdrawing effects may occur via inductive, resonance, or other electrostatic effects.…”

“…Similar electrophilic activation has been observed from cationic functional groups and structures. 2 Depending on the cationic group, very strong electron-withdrawing effects may occur via inductive, resonance, or other electrostatic effects. Multiply charged cationic electrophiles (i.e., dications or trications) have even been described as superelectrophiles on the basis of their high electrophilic reactivities.…”

Preparation of aryl-substituted 2-oxyindoles by superelectrophilic chemistry

“…Previous work from our group and others has demonstrated the ability of pyridinium groups to strongly activate adjacent electrophiles. 9 This suggested to us that ionization of alcohol 4 would give a highly reactive dicationic - or superelectrophilic – species, 10 an intermediate likely to be useful in Friedel-Crafts-type reactions.…”

Superelectrophilic carbocations: preparation and reactions of a substrate with six ionizable groups

“…Numerous studies from our group and others have shown that relatively stable cationic centers – such as ammonium, phosphonium, and pyridinium groups – may also be part of superelectrophilic systems [10]. Recently, we described the chemistry of tri-, tetra-, and pentacationic electrophiles based on the triarylmethyl cation scaffold ( 3–5 , Scheme 1) [11–12].…”