TABLE 2.
Yields of the isolated products from Suzuki–Miyaura cross-coupling reactions of thiophene-2-boronic esters and aryl halides with different catalysts.
| Thiophene-2-boronic esters | Aryl halides | Time (min) | Yield (%) | ||
|---|---|---|---|---|---|
| Pd2(dba)3/L1 | Pd(PPh3)4 | ||||
| 1 |
|
|
15 | 96 | 83 |
| 2 |
|
|
15 | 95 | 76 |
| 3 |
|
|
15 | 92 | 72 |
| 4 |
|
|
15 | 93 | 81 |
| 5 |
|
|
15 | 97 | 81 |
| 6 |
|
|
30 | 88 | 24 |
| 7 |
|
|
30 | 90 | 18 |
| 8 |
|
|
30 | 90 | 31 |
| 9 |
|
|
30 | 91 | 48 |
Reaction conditions: 1 equiv. of thienyl halide, 1 or 2 equiv. of thiophenylboronic ester, 5 equiv. of K2CO3, THF (5 L mol-1), H2O, 0.1 mol% Pd2(dba)3 + L1, reflux, within 15–30 min, 1 mol% Pd(PPh3)4, reflux, within 2 h.