Table 1. Calculated Thermodynamic Parametersa for the keto-(k)/enol-Forms (e) of the Final Products; Values are Given in kcal/mol.
| entry | substrate | ΔErel | ΔHrel | TΔSrel | ΔGrel (k–e) |
|---|---|---|---|---|---|
| 1 | imidazolidin-2-one | –22.60 [−22.86]b | –22.74 [−23.01]b | –0.69 [−0.69]b | –22.05 [−22.31]b |
| 2 | imidazolidine-2-thione | –19.84 [−20.36]b | –20.14 [−20.57]b | –1.15 [−0.85]b | –18.99 [−19.71]b |
| 3 | oxazolidin-2-one | –20.53 [−21.50]b | –20.70 [−21.71]b | –0.50 [−0.55]b | –20.20 [−21.15]b |
| 4 | oxazolidine-2-thione | –14.99 [−16.11]b | –15.35 [−16.45]b | –0.86 [−0.78]b | –14.49 [−15.66]b |
| 5 | imidazolidin-2-one-DMSO | –16.18c | –15.99c | 0.60c | –16.60c |
| 6 | imidazolidine-2-thione-DMSO | –19.08c | –18.65c | 1.36c | –20.02c |
| 7 | oxazolidin-2-one-DMSO | –16.14c | –16.01c | 0.70c | –16.71c |
| 8 | oxazolidine-2-thione-DMSO | –17.64c | –17.97c | –1.36c | –16.61c |
a
Calculated using the B3LYP/6-311++G(d,p) basis set, and the values are given relative to the enol-form in all reactions.
b
Values are calculated in DCM, and values in brackets are calculated in DMSO.
c
Values calculated in the presence of explicit DMSO molecules.