Table 1. Optimizing Conditions for the Mitsunobu Reaction with Nitrosobenzenea.
| entry | PhNO (x equiv) | Ph3P (y equiv) | c (1a) (mM) | T (°C) | conv.b (%) |
|---|---|---|---|---|---|
| 1c | 1 | 2 | 75 | 25 | 7 |
| 2 | 1 | 4 | 75 | 25 | 25 |
| 3 | 2.5 | 2.5 | 75 | 25 | 43 |
| 4 | 3 | 2 | 75 | 25 | 23 |
| 5 | 2.5 | 2.5 | 9.4 | 25 | 67 |
| 6 | 2.5 | 2.5 | 2.4 | 25 | 10 |
| 7 | 2 | 2 | 9.4 | 25 | 58 |
| 8 | 3 | 3 | 9.4 | 25 | 72 |
| 9 | 2.5 | 2.5 | 9.4 | 0 | 82 |
| 10 | 2.5 | 2.5 | 9.4 | –25 °C | 52 |
a
Conditions: 1a (0.15 mmol), 2a (0.18 mmol), PhNO (x equiv relative to 1a), Ph3P (y equiv relative to 1a) added in the form of solution in acetonitrile (V = 2–64 mL, to adjust the concentration); reaction time: 30 min; see the Supporting Information for details.
b
Determined by 1H NMR.
c
Ph3P added as a solid. Reaction time: 20 h.