substituents
Activation energies, Ea (kcal/mol)
Enthalpy changes, ΔH (kcal/mol)
Endo
Exo
Endo
Exo
-CH
3
+12.26
+11.87
-55.54
-55.54
-OH
+7.30
+6.48
-56.93
-56.97
-CN
+4.34
+5.16
-58.75
-58.75
-Cl
+8.60
+7.88
-56.30
-56.30
Table 4:
Energetics of the reactions of 4,4-disubstituted cyclobutenone with 1,3-butadiene.
