Table 1. Optimization of the Reaction Conditions.
| entry | TM catalyst | oxidant (2 equiv) | remarks |
|---|---|---|---|
| 1 | [RuCl2(p-cymene)]2 | air | no reaction |
| 2 | [RuCl2(p-cymene)]2 | K2S2O8 | no reaction |
| 3 | [RuCl2(p-cymene)]2 | Cu(OAc)2 | no reaction |
| 4 | [RuCl2(p-cymene)]2 | PhI(OAc)2 | no reaction |
| 5 | [RuCl2(p-cymene)]2 | MesI(OAc)2 | no reaction |
| 6 | [RuCl2(p-cymene)]2 | PhI(TFA)2 | 60%a |
| 7 | [RuCl2(p-cymene)]2 | PhI(TFA)2 | 46%a under air |
| 8b | [RuCl2(p-cymene)]2 | PhI(TFA)2 | 90%a |
| 9c | [RuCl2(p-cymene)]2 | PhI(TFA)2 | complex mixture |
| 10 | RuCl3·H2O | PhI(TFA)2 | no reaction |
| 11 | Pd(OAc)2 | PhI(TFA)2 | no reaction |
Product by HPLC.
3 equiv of the oxidant used.
[Ir(dF(CF3)ppy)2(dtbbpy)]PF6 (5 mol %) used instead of 4CzIPN.
