Table 1 Reaction optimizationa.
From: Reaction scope and mechanistic insights of nickel-catalyzed migratory Suzuki–Miyaura cross-coupling
| |||
|---|---|---|---|
Entry | Deviation from standard conditions | Yield, % | 3a:4a |
1 | No | 89 (82)b | 27:1 |
2 | No Et3SiH | 6 | 4:1 |
3 | Zn instead of Et3SiH | 35 | 12:1 |
4 | ZnMe2, MeMgBr instead of Et3SiH | Trace | – |
5 | KF, Na2CO3, Cs2CO3, NaOH instead of LiOH | Trace | – |
6 | No TBAB | 8 | 2:1 |
7 | NiCl2 instead of NiI2 | Trace | – |
8 | NiBr2 instead of NiI2 | 46 | 21:1 |
9 | Ni(COD)2, no Et3SiH | 12 | 2:1 |
10 | L1 | 28 | 2:1 |
11 | L2 | 81 | 51:1 |
12 | L3 | 78 | 35:1 |
13 | L4 | 76 | 1:77 |
14 | NiI2/BC (5 mol%) | 72 | 19:1 |
15 | 60 °C, 24 h | 71 | 8:1 |
16 | 60 °C, no Et3SiH | 10 | 6:1 |
- aStandard conditions: NiI2 (15.6 mg, 0.05 mmol, 10 mol%), BC (18.0 mg, 0.05 mmol, 10 mol%), Et3SiH (20 μL, 0.13 mmol, 25 mol%), 1a (145.0 mg, 0.5 mmol, 1.0 equiv), 2a (127.5 mg, 0.75 mmol, 1.5 equiv), LiOH (29.9 mg, 1.25 mmol, 2.5 equiv), TBAB (161.2 mg, 0.5 mmol, 1.0 equiv), DMA (4 mL). Yields were determined by GC with 1,3,5-trimethoxybenzene as the internal standard
- bIsolated yield
