Table 2. The effect of desiccants a .
| ||||
| Entry | Desiccant | Amount (mg mmol–1) | Yield (%) | Er |
| 1 | None | — | 0 | — |
| 2 | MS 5 Å (A) | 100 | 32 | 99 : 1 |
| 3 | MS 5 Å (A) | 300 | 77 | 99 : 1 |
| 4 | MS 5 Å (A) | 500 | 88 | 99 : 1 |
| 5 | MS 5 Å (A) | 1000 | 95 | 99 : 1 |
| 6 | MS 4 Å (A) | 500 | 32 | 97 : 3 |
| 7 | MS 3 Å (A) | 500 | 26 | 98 : 2 |
| 8 | MS 5 Å (B) | 500 | 13 | 96 : 4 |
| 9 | MS 5 Å (C) | 500 | 16 | 91 : 9 |
| 10 | MS 5 Å (D) | 500 | 25 | 97 : 3 |
| 11 | MS 5 Å (E) | 500 | 67 | 98 : 2 |
| 12 | MS 5 Å (F) | 500 | 94 | 99 : 1 |
| 13 | Na2SO4 | 500 | 0 | — |
| 14 | CaSO4 | 500 | 0 | — |
| 15 | MgSO4 | 500 | 0 | — |
aReaction conditions: 3 (1.0 mmol), 4 (1.1 mmol), catalyst 1a (0.10 mmol), Fe(Pc) (0.10 mmol), PPh3 (2.0 mmol), toluene (2 mL), desiccant (0–1000 mg) for 24–48 h at room temperature under air atmosphere. Methods for activation of molecular sieves: A: heated using a heat gun (ca. 450 °C) in vacuo (ca. 0.1 mmHg) for 5 min; B: not activated; C: heated in an oven (140 °C) for 24 h; D: heated using a microwave (1000 W for 1 min, three times); E: heated using an oil bath (200 °C) in vacuo (ca. 0.1 mmHg) for 24 h; F: heated using a gas burner (>1000 °C) in vacuo (ca. 0.1 mmHg) for 5 min.