Carbon−Hydrogen and Carbon−Carbon Bond Activation of Cyclopropane by a Hydridotris(pyrazolyl)borate Rhodium Complex

Generation of the 16-electron fragment {[HB(3,5-dimethylpyrazolyl)3]Rh(CNCH2CMe3)} (Tp‘RhL) in the presence of cyclopropane results in C−H activation of the hydrocarbon. The cyclopropyl hydride complex rearranges in benzene solvent to the metallacyclobutane complex Thermolysis of the rhodacyclobutane complex produces an η2-propylene complex. The related complex Tp‘Rh(CN-2,6-xylyl)(C2H4) has been structurally characterized and displays η3-Tp‘ coordination, both in the solid state and in solution. Thermolysis of the rhodacyclobutane complex in the presence of neopentyl isocyanide leads to insertion of isocyanide into both Rh−C bonds of the metallacycle. Cyclobutane undergoes C−H but not C−C bond cleavage.