Figure 4. Transition state structures for the rotational enantiomerization and automerization of (E)-1 and (E)-2 calculated at the B3LYP/6-31G* level.
(E)-1, R = H (E)-2, R = Me
Planar
"Planar"
Perp.
Ph(N)

Perp.
Ph(Im)
Sym.
Cleft

Sym.
Cleft'
Cleft
twisted