Table 2.
Optimization of reaction conditions of PhI and dibromothiophene by DHAP a.
| Entry | Pd Catalyst | Base | Ligand | Mn b (kDa) | PDI b | Yield c (%) |
|---|---|---|---|---|---|---|
| 1 | Pd(PPh3)4 | Cs2CO3 | P(o-OMePh)3 | 7.8 | 3.89 | 27.6 |
| 2 | Pd(OAc)2 | Cs2CO3 | P(o-OMePh)3 | 5.7 | 3.64 | 19.7 |
| 3 | Pd2(dba)3 | Cs2CO3 | P(o-OMePh)3 | 11.0 | 2.09 | 49.6 |
| 4 | Pd(PPh3)2Cl2 | Cs2CO3 | P(o-OMePh)3 | 8.9 | 2.47 | 22.2 |
| 5 | Pd2(dba)3 | K2CO3 | P(o-OMePh)3 | 12.2 | 1.66 | 64.1 |
| 6 | Pd2(dba)3 | K2CO3 | P(o-tol)3 | 10.1 | 1.92 | 52.4 |
| 7 | Pd2(dba)3 | K2CO3 | PCy3·HBF4 | 8.6 | 3.49 | 26.1 |
| 8 | Pd2(dba)3 | KOAc | P(o-OMePh)3 | 9.1 | 2.38 | 39.2 |
a DHAP was carried out in the presence of palladium catalyst (5 mol %), phosphine ligand (10 mol %), base (2.5 equiv.) and additive (30 mol %) at 110 °C for 72 h. b Determined by gel permertion chromatography (GPC) on polystyrene standards in dichlorobenzene (DCB). c The products were obtained by reprecipitation from methanol after Soxhlet extraction.