Table 1.
| |||||||
---|---|---|---|---|---|---|---|
entry | 1a:2:3a | solvent | temp. (°C) |
conc. (M) |
time (h) |
Pd(OAc)2/ PCy3 mol (%) |
4a[a] (%) |
1 | 1:3:3 | THF | 110 | 0.1 | 24 | 5/10 | 0 |
2 | 1:3:3 | DME | 110 | 0.1 | 24 | 5/10 | 0 |
3 | 1:3:3 | Dioxane | 110 | 0.1 | 24 | 5/10 | 10 |
4 | 1:3:3 | CPME | 110 | 0.1 | 24 | 5/10 | 15 |
5 | 1:3:3 | CPME | 80 | 0.1 | 24 | 5/10 | 30 |
6 | 1:3:3 | CPME | 60 | 0.1 | 24 | 5/10 | 20 |
7 | 1:3:3 | CPME | 80 | 0.2 | 24 | 5/10 | 40 |
8 | 3:3:1 | CPME | 80 | 0.2 | 24 | 5/10 | 65 |
9 | 3:3:1 | CPME | 80 | 0.3 | 24 | 5/10 | 68 |
10 | 3:3:1 | CPME | 80 | 0.4 | 24 | 5/10 | 69 |
11 | 4:4:1 | CPME | 80 | 0.2 | 24 | 5/10 | 74 |
12 | 4:4:1 | CPME | 80 | 0.2 | 24 | 5/15 | 80 |
13 | 4:4:1 | CPME | 80 | 0.2 | 24 | 5/20 | >99 |
Yield determined by 1H NMR analysis of crude mixture with internal standard CH2Br2; less than 4% of gamma-arylated product was detected by NMR.