NMR spectra and configuration of some methylallylic anions

The NMR spectra of trans-(I) and cis-3-methyl-trans-1-phenylallyl anion (II), of cis-1-methylpentadienyl anion, and of cis-1-methyl-5-oxapentadienyl anion are described. I is obtained by abstraction of a proton from 1-phenyl-trans-2-butene at low temp. At 0 Deg it largely isomerizes to II. Several aspects of the configuration of these anions are discussed. [on SciFinder (R)