1442
J . Am. Chem. Soc. 1991, 113, 1442-1444
15% N M R yield of another ZrCp, derivative, which was indistinguishable from a species obtained by treating 1 ,I-bis($cyclopentadienyl)-2,3,4,5-tetraphenyl-1-zirconacyclopentadiene with PhLi. This contamination hampered attempts to obtain 7a as a pure compound. Furthermore, its ' H and I3C N M R spectra were relatively ~ n i n f o r m a t i v e . ' ~ , ' ~Fourthly, treatment of C ~ , Z ~ ( C = C T O I - with ~ ) ~ 2 equiv of PhLi in the presence of P h C E C P h produced, after protonolysis with 3 N HCI, a 62% G L C yield of (Z)-PhCH=CHTol-p without producing ( Z ) stilbene (
