Table 1. Reaction Optimizationa.
| entry | catalyst | 2 | solvent | conv. (%)b | rr (3,4/1,2)b | trans/cisb |
|---|---|---|---|---|---|---|
| 1 | Ni(cod)2 | 2a | toluene | nrc | ||
| 2 | Ni(cod)(DQ) | 2a | toluene | nr | ||
| 3 | NiCl2(PPh3)2 | 2a | toluene | nr | ||
| 4 | Pd(OAc)2 | 2a | toluene | 12 | >20:1 | 1.4:1.0 |
| 5 | PdCl2(cod) | 2a | toluene | nr | ||
| 6 | (CPhos)Pd(G3) | 2a | toluene | nr | ||
| 7 | C1 | 2a | toluene | nr | ||
| 8 | Pd2(dba)3 | 2a | toluene | 37 | >20:1 | 1.3:1.0 |
| 9 | Pd2(dba)3/L1 | 2a | toluene | 9 | >20:1 | 2.0:1.0 |
| 10 | Pd2(dba)3/PCy3d | 2a | toluene | <5 | nde | nd |
| 11 | Pd2(dba)3 | 2a | CH2Cl2 | 31 | >20:1 | 1.5:1.0 |
| 12 | Pd2(dba)3 | 2a | THF | 64 | >20:1 | 1.2:1.0 |
| 13 | C2 | 2a | THF | 38 | >20:1 | 2.0:1.0 |
| 14 | C3 | 2a | THF | 41 | >20:1 | 1.2:1.0 |
| 15 | C4 | 2a | THF | 69 | >20:1 | 1.0:1.0 |
| 16 | C4/L1 | 2a | THF | nr | ||
| 17 | C4/PCy3d | 2a | THF | 18 | >20:1 | 1.0:1.0 |
| 18 | C3 | 2b | THF | nr | ||
| 19 | C4 | 2b | THF | 47 | >20:1 | nag |
| 20f | C4 | 2b | THF | 23 | >20:1 | na |
a
Reaction conditions: 1a (0.1 mmol), 2a–b (0.12–0.15 mmol).
b
Determined by 1H NMR using an internal standard.
c
No reaction.
d
10 mol % of PCy3.
e
Not determined.
f
At 60 °C.
g
Not applicable.