Table 1. Optimization of Cross-Coupling with Potassium Alkenyltrifluoroborates.
entry | palladium source (loading) | base | solvent | P:SPa |
---|---|---|---|---|
1 | XPhos-Pd-G2 (4 mol %) | Cs2CO3 | 1:1 CPME/H2O | trace product |
2 | SPhos-Pd-G2 (4 mol %) | K2CO3 | 1:1 CPME/H2O | trace product |
3 | Pd2dba3/cataCXium A (4 mol %) | Cs2CO3 | 1:1 CPME/H2O | 0.50:1.0 |
4 | (Ph3P)2PdCl2 (6 mol %) | Cs2CO3 | 1:1 CPME/H2O | 2.57:1.0 |
5 | (Ph3P)2PdCl2 (6 mol %) | Cs2CO3 | 1:1 toluene/H2O | 2.00:1.0 |
6 | (Ph3P)2PdCl2 (6 mol %) | Cs2CO3 | 9:1 toluene/H2O | 2.50:1.0 |
7 | Pd(dppf)Cl2(6 mol %) | Cs2CO3 | 1:1 toluene/H2O | 3.10:1.0 |
8 | Pd(dppf)Cl2 (6 mol %) | Cs2CO3 | 1:1 CPME/H2O | 1.85:1.0 |
Product:side products.