Four commonplace concerted reactions are examined using (i) correlation diagrams, (ii) frontier molecular orbital analyses for transition states, (iii) Zimmerman-Dewar analyses for transition states and (iv) modified Zimmerman-Dewar analyses for transition states. Only the latter approach is consistently satisfactory.
Hückel-Möbius transition states; correlation diagrams; Frontier-orbital analyses; modified Zimmerman-Dewar arguments
