Designed Synthesis of New <i>ortho</i>-Carborane Derivatives: from Mono- to Polysubstituted Frameworks

The use of nucleophilic and electrophilic processes allow the designed synthesis of several B-iodinated derivatives of o-carborane. Because of the straightforward Pd-catalyzed conversion of B−I to B−C bond with Grignard reagents, such as methylMgBr and biPhenylMgBr, both, symmetrical 3,6-R2-1,2-closo-C2B10H10 and asymmetrical 3-I-6-Me-1,2-closo-C2B10H10 could be obtained. Not only conventional reactions in solution have been studied but also a highly efficient, clean and fast solvent-free procedure has provided successful results to regioselectively produce B-iodinated o-carborane derivatives by a careful control of the reaction conditions. The high number of nonequivalent leaving groups in boron iodinated o-carborane derivatives opens the possibility through B−C coupling to materials with novel possibilities and to self-assembling due to the enhanced polarizability of the C−H bond.