Table 3.
Relative free energies (carbene 3/ylide 2, ylide 4/betaine 6 and carbene 5/betaine 6) computed at the DFT B3LYP/6-31+G(d,p) level in the gas phase or with the PCM model for the corresponding solvent at 298 K. Calculated data are based on the most stable conformer of 2−6.
 | |||||
| entry | equilibrium system | ΔG3-2, kcal·mol−1 | |||
| gas phase | DCM | THF | DMSO | ||
equilibrium 2
3 (ΔG3-2, kcal·mol−1) | |||||
| 1 | a | –1.5 | 9.6 | – | 12.3 |
| 2 | b | –0.5 | 10.2 | 9.5 | 12.8 |
| 3 | e | –1.3 | 7.9 | – | 10.1 |
| 4 | i | –0.8 | 9.6 | 9.3 | 12.4 |
| 5 | j | –2.7 | 6.8 | – | 9.5 |
| equilibrium 4
5
6 (ΔG4-6/ΔG5-6, kcal·mol−1) | |||||
| 6 | a | –11.4/–8.6 | 1.5/16.0 | – | 4.0/20.0 |
| 7 | b | –12.4/–9.0 | 1.2/15.7 | 0.5/14.6 | 4.0/20.5 |
| 8 | e | –11.6/–8.8 | 1.9/14.4 | – | 4.0/17.9 |
| 9 | i | –10.9/–7.0 | 1.8/16.3 | – | 3.8/20.1 |
| 10 | j | –11.3/–9.1 | 2.1/14.1 | – | 4.3/18.0 |