Table 1.
Optimization of reaction conditions.a
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| Catalyst (mol %) | Ligand (mol %) | Base (equiv) | Equiv of 1a | Yield (%) | |
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| 1 | CuI | DMEDA (20) | K3PO4 (1.5) | 1.0 | 22b |
| 2 | CuI (10) + 1 equiv AgNO3 | DMEDA (20) | K3PO4 (1.5) | 1.0 | n.d. |
| 3 | CuI (10) | DMEDA (20) | K2CO3 (1.5) | 1.0 | 16b,c |
| 4 | Cu(OTf)2 (10) | glyme (20) | K2CO3 (2.5) | 1.0 | 33b |
| 5 | Cu(OTf)2 (10) | diglyme (20) | K2CO3 (2.5) | 1.5 | 42b |
| 6 | Cu(OTf)2 (15) | diglyme (30) | K2CO3 (2.5) | 2.0 | 44b |
| 7 | CuI (15) | diglyme (30) | K 2 CO 3 (3.0) | 2.0 |
76
b
74 d |
| 8 | CuI (15) | diglyme (30) | Cs2CO3 (3.0) | 2.0 | – |
| 9 | CuCl | diglyme (30) | K2CO3 (3.0) | 2.0 | – |
| 10 | CuBr | diglyme (30) | K2CO3 (3.0) | 2.0 | – |
| 11 | CuI (15) | diglyme (30) | K2CO3 (3.0) | 2.0 | –e |
| 12 | CuI (15) | diglyme (30) | K2CO3 (3.0) | – | –f |
aCommon reaction conditions: 18 h at 120 °C, in degassed p-xylene under Ar atmosphere. bYields determined via GC–MS at a 100 µmol scale. cReaction carried out in DMF. dIsolated yields on a 200 µmol scale. e2.0 equiv of KI added. f2,2-Diiodobiphenyl as starting material.