ChemInform Abstract: Relative Reactivities of the Small Closo Carboranes 1,6-C2B4H6 and 2,4-C2B5H7 and of closo-1,10-C2B8H10 Toward “Electrophilic” Reagents.
Abstract
The relative reactivities of the title carboranes (I)-(III) and some of their derivatives toward electrophilic reagents of the type RX/AlCl3 (RX: MeCl, EtCl, Cl2, Br2) are reported from competition studies.
ChemInform Abstract
The relative reactivities of the title carboranes (I)-(III) and some of their derivatives toward electrophilic reagents of the type RX/AlCl3 (RX: MeCl, EtCl, Cl2, Br2) are reported from competition studies. Among the three parent carboranes, (I) is the most reactive one. The reactivity order (I) > (II) and (I) > (III) is in qualitative agreement with MO calculated framework charges. Alkyl substituents on (I) enhance the reactivity of the compound toward an electrophilic substitution, whereas halogen substituents decrease the reactivity. However, the reactivity of chloro-substituted compounds of (II) is greater than that of the parent carborane. The nature (halogen or alkyl) and cage position of a substituent on (I) appear to have little or no influence on the site of electrophilic substitution.
