Distonic carbodications

An aromatically stabilized carbodication, 37, was prepared by Komatsu and coworkers in strongly acidic media. The ion undergoes deprotonation to give a conjugated monocation, 38, in less acidic media. The corresponding distonic carbodications with 1,4-phenylene, 1,5-naphthalene, and 1,8-naphthalene spacer groups (39, 40, and 41) have been prepared and well characterized. ... 

There has been considerable experimental and theoretical work related to carbodications, many of which may be considered distonic... 

Water elimination in the superacidic solution is a highly exothermic step, but nevertheless the 2,6-adamantadiyl dication 34 is not formed. This observation suggests that structures like 34 can be distonic superelectrophiles. As in the case of other 1,4- and 1,5-carbodications, the 2,6-adamantadiyl dications are stabilized and persistent when the carbenium centers bear an aryl substituted (vide infra). 

Among other distonic superelectrophiles described in the literature, there are carbo-onium dications. These include carbo-carboxonium dications, carbo-ammonium dications, and related ions. Despite the separation of charge in these superelectrophiles, some have been shown to have very high electrophilic reactivities. I. ike the carbodications described previously, the discussion here is limited to those systems that have been shown to have electrophilic reactivities greater than the related monocationic onium ions, as well as structural criteria supporting their designation as a distonic superelectrophilic species. 

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