Stereoselective Addition of Benzophenone to (C5Me5)Hf(2,3-dimethyl-1,3-butadiene)Cl

The reaction of (C5Me5)Hf(s-cis-C6H10)Cl with benzophenone results in sequential insertion of two ketone molecules in the Hf-diene bond through adduct intermediates. The final 1,3-dioxa-2-hafnacyclonon-6-ene has a cis-configuration around the double bond, in contrast with related products from (C5H5)2Zr(diene).