Table 3.
| ||||||
---|---|---|---|---|---|---|
entry | 1a:2a:3a | solvent | T (°C) | time (h) | Pd: NiXantPhos (mol %) | 4aa (%) |
1 | 2:1:2 | THF | 80 | 12 | 10:20 | 45 |
2 | 2:1:3 | THF | 80 | 12 | 10:20 | 0 |
3 | 1:2:2 | THF | 80 | 12 | 10:20 | 52 |
4 | 1:2:2 | THF | 50 | 12 | 10:20 | 53 |
5 | 1:2:2 | THF | R.T. | 12 | 10:20 | 60 |
6 | 1:2:2 | THF | R.T. | 6 | 10:20 | 67 |
7 | 1:2:2 | THF | R.T. | 1 | 10:20 | 80 |
8 | 1:2:2 | THF | R.T. | 0.5 | 10:20 | 86 |
9 | 1:2:2 | THF | R.T. | 0.25 | 10:20 | 76 |
10 | 1:2:2 | THF | R.T. | 0.5 | 5:10 | 67 |
11 | 1:2:2 | THF | R.T. | 0.5 | 5:10 | 64b |
12 | 1:2:2 | CPME | R.T. | 0.5 | 10:20 | 0 |
13 | 1:2:2 | DME | R.T. | 0.5 | 10:20 | 58 |
14 | 1:2:2 | dioxane | R.T. | 0.5 | 10:20 | 0 |
15 | 1:2:2 | hexanes | R.T. | 0.5 | 10:20 | 0 |
16 | 1:2:2 | toluene | R.T. | 0.5 | 10:20 | 0 |
Yields determined by 1H NMR analysis of crude mixture with CH2Br2 as internal standard.
concentration 0.2 M.