Table 1.
Entry a | n | M | Additive | Lewis Acid | Solvent | Yield b |
---|---|---|---|---|---|---|
1 | 4 | Li | BF3·OEt2 | THF | ND c | |
2 | 4 | SiMe3 | BF3·OEt2 | CH2Cl2 | ND c | |
3 | 4 | MgBr | BF3·OEt2 | THF | ND c | |
4 | 4 | MgBr | CuBr·SMe2 | BF3·OEt2 | THF | 63 |
5 | 4 | MgBr | CuBr·SMe2 | BF3·OEt2 | Et2O | 32 |
6 | 4 | MgBr | CuI | BF3·OEt2 | THF | ND c |
7 | 4 | MgBr | CuOTf | BF3·OEt2 | THF | ND c |
8 | 3 | MgBr | CuBr·SMe2 | BF3·OEt2 | THF | 60 |
9 | 2 | MgBr | CuBr·SMe2 | BF3·OEt2 | THF | 65 |
10 | 1 | MgBr | CuBr·SMe2 | BF3·OEt2 | THF | ND c |
a All reactions were performed using 0.3 mmol of 2 in dry solvent. See, Experimental section for a representative procedure. b Isolated yields. c Not detected.