Intramolecular activation of pendant alkenyl group as a tool for modification of the zirconocene framework

The diphenyl zirconocene [(η5-C5H5){η5-C5H4CMe2(CH2)2CHCH2}ZrPh2] (2) was readily obtained from the corresponding zirconocene dichloride 1 and two equivalents of phenyllithium. Upon thermal treatment at 80 °C, complex 2 released benzene, with concomitant activation of the pendant double bond and formation of intramolecularly α-tethered zirconaindane [(η5-C5H5){η5,η1,η1-C5H4CMe2(CH2)2CHCH2C6H4}Zr] (3). Both Zr–C σ-bonds in 3 easily undergo nucleophilic reactions with two equivalents of HCl or one equivalent of Cl2PPh giving rise to zirconocene dichlorides with pendant phenyl group [(η5-C5H5){η5-C5H4CMe2(CH2)4Ph}ZrCl2] (4) or with 1-phenylphosphindolinyl moiety [(η5-C5H5){η5-C5H4CMe2(CH2)2cyclo-CHCH2C6H4P(Ph)}ZrCl2] (5), respectively.