Figure 2. Transition state structures for the rotational enantiomerization and automerization of (E)-1 (left column) and (Z)-1 calculated at the B3LYP/6-31G* level.
(E)-isomer (Z)-isomer
planar
Perp. Ph(N)

Perp. Ph(Im)
symmetric
Cleft
twisted

Cleft
symmetric