Table 5. Initial Screening Experiments to Racemize (P)-6.
| Entry | Solvent | Conditionsa | %eeb | LC area% |
|---|---|---|---|---|
| 1 | NMP | 200 °C (2 h) | 99.1 | 94.4 |
| 2 | NMP | 200 °C (8 h) | 96.3 | 80.3 |
| 3 | DMI | 250 °C (4 h) | 61.1 | 59.5 |
| 4 | sulfolane | 250 °C (4 h) | 75.5 | 86.3 |
| 5 | sulfolane | 280 °C (4 h) | 50.9 | 76.1 |
| 6 | diphenyl ether | 250 °C (4 h) | 69.1 | 97.5 |
| 7 | 1-octadecenec | 250 °C (4 h) | 74.2 | 98.5 |
| 8 | anisoled | 315 °C (0.3 h) | 2.0 | 99.1 |
a
Experiments performed at 100 mg scale.
b
Chiral purity at t0 = 99.6% ee.
c
Slurry-to-slurry transformation.
d
Experiment was performed in a plug-flow reactor. Adapted with permission from ref (3). Copyright 2022 The American Chemical Society.