| Entry | Mole ratio of d1/d2 | N2 condition | solvent | Temp (˚C) | Time (h) | Yield % |
| 1 | 1/0.5 | N2 | CH3CN | r.t | 10 | 36 |
| 2 | 1/0.6 | N2 | CH3CN | r.t | 10 | 70 |
| 3 | 1/0.65 | N2 | CH3CN | r.t | 6 | 92 |
| 4 | 1/0.65 | -- | CH3CN | r.t | 6 | 0 |
| 5 | 1/0.7 | N2 | CH3CN | r.t | 6 | 35 |
| 6 | 1/0.65/2 equiv NaOAc | N2 | CH3CN | r.t | 10 | 20 |
| 7 | 1/0.65/2 equiv Cu (OAc)2 | N2 | CH3CN | r.t | 48 | 60 |
| 8 | 1/0.65/2 equiv CuCl | N2 | CH3CN | r.t | 6 | Trace |
| 9 | 1/0.65 | N2 | THF | r.t | 10 | 20 |
| 10 | 1/0.65 | N2 | CH2Cl2 | r.t | 12 | 0 |
| 11 | 1/0.65/2 equiv CuCl | N2 | THF | r.t | 10 | 0 |
| 12 | 1/0.65/2 equiv Cu (OAc)2 | N2 | THF | r.t | 10 | Trace |