In diethyl ether solution at-40" t-butyllithium and norbornene after carbonation give 4, 4dimethylpentanoic acid, a product arising from addition of t-butyllithium to liberated ethylene from the solvent. Under the same conditions t-butyllithium adds to vinyltrimethylsilane yielding, after carbonation, 2-trimethylsilyl-4.4-dimethylpentanoic acid (VII). The nmr spectra of the products from hydrolysis or carbonation show that the product ...