Icosahedral carboranes as scaffolds for congested regioselective polyaryl compounds: the distinct distance tuning of C-C and its antipodal B-B.

Four-fold aryl substituted o-carborane derivatives with defined patterns of substitution at the antipodal region of the cluster carbon atoms have been achieved. It is proven that this region is congested but lacks steric hindrance. Also, the two antipodal sites Cc-Cc and B9-B12 are affected very distinctly by electron donor substituents.