Table 1.
entry | [Cu] catalyst | solvent | yielda |
---|---|---|---|
1 | CuBr2 | MeCN | 68% |
2 | CuCl2 | MeCN | 2% |
3 | CuBr | MeCN | 31% |
4 | Cu(TFA)2 | MeCN | 0% |
5b | Cu(TFA)2 | MeCN | 50% |
6c | CuBr2 | MeCN | 62% |
7 | CuBr2 | CHCl3/EtOAc | 45% |
8 | CuBr2 | THF | 67% |
9 | CuBr2 | DMF | 71% |
10 | CuBr2 | DMSO | 93%d |
GC yield using Bn2O as an internal standard.
With 30 mol% LiBr.
Performed over 24 hours.
Isolated Yield.