Table 1. Oxidative Coupling of (1a) and (2a) under Various Conditionsa.
| entry | catalyst (wt %) | solvent | oxidant (equiv) | T (°C) | yieldb (%) |
|---|---|---|---|---|---|
| 1 | Fe3O4–CND (10) | H2O | r.t | Nr | |
| 2 | Fe3O4–CND (10) | H2O | 90 | 5 | |
| 3 | Fe3O4–CND (10) | H2O | TBHP (1) | 90 | 62 |
| 4 | Fe3O4–CND (10) | H2O | TBHP (2) | 90 | 94 |
| 5 | H2O | TBHP (2) | 90 | 25 | |
| 6 | Fe3O4–CND (10) | CH3CN | H2O2 (2) | 90 | trace |
| 7 | CND (10) | H2O | TBHP (2) | 90 | 35 |
| 8 | Fe3O4–CND (10) | PhCH3 | TBHP (2) | 90 | 95 |
| 9 | Fe3O4–CND (10) | C2H5OH | TBHP (2) | 90 | 65 |
| 10 | Fe3O4 (10) | H2O | TBHP (2) | 90 | 57 |
| 11 | Fe3O4–citrate (10) | H2O | TBHP (2) | 90 | 60 |
a
Reaction conditions: 1a (1.5 mmol), 2a (0.5 mmol), oxidant 1–2 equiv and solvent 2 mL, 16 h.
b
Yields of isolated product.