Quasi-borinium cation Lewis acidity

QUASI-BORINIUM CATION BASED ON COBALT BIS(DICARBOLLIDE) ITS LEWIS ACIDITY AND C-H AND C-X BOND ACTIVATION... 

In the chemistry of polyhedral boron hydrides, boron-centered cations were postulated to be key intermediates of an electrophile-induced nucleophilic substitution mechanism that is responsible for the formation of a variety of boron-substituted derivatives [14], Such boron-centered cations can be easily generated by abstraction of a hydride by the treatment of polyhedral boron hydrides with Lewis or Bronsted acids [15], Similar to the classical chelate-restrained borinium cations based on 3-coordinate boron, these species, which we called quasi-borinium cations, have an unstabilized p orbital and are strong electrophiles (Scheme 6.1). Such quasi-borinium cations are highly reactive and react with even weak nucleophiles, such as ether or nitrile solvent molecules giving the corresponding oxonium and nitrilium derivatives whose properties are close to those of similar complexes of transition metals [15-17]. 

Here we describe the reactions of C-H activation of arenes and C-X activation of halogen alkanes with a quasi-borinium cation generated from the iodonium derivative of cobalt bis(dicarbollide) [/u.-8,8 -I-3,3 -Co(1,2-C2B9Hjq)2], as well as an assessment of the Lewis acidity of this highly reactive intermediate. 

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