Table 1.
Optimization of the reaction conditions.
|
| ||||
|---|---|---|---|---|
|
Run[a] |
L |
[H]/additive |
Time [h] |
Yield 3 a [%][b] |
|
1 |
[Ni(L1)Cl2] |
Zn/– |
16 |
36 |
|
2 |
[Ni(L1)Cl2] |
Mn/– |
16 |
16 |
|
3 |
[Ni(L1)Cl2] |
TDAE/– |
16 |
0 |
|
4[c,d] |
[Ni(L2)Cl2] |
Zn/– |
16 |
0 |
|
5[c] |
[Ni(L3)Cl2] |
Zn/– |
16 |
55 |
|
6 |
[Ni(L3)Br2] |
Zn/– |
18 |
54 |
|
7[c,d] |
[Ni(L4)Cl2] |
Zn/– |
16 |
8 |
|
8 |
[Ni(L5)Cl2] |
Zn/– |
16 |
59 |
|
9[c] |
[Ni(L6)Cl2] |
Zn/– |
16 |
48 |
|
10[c,d] |
[Ni(L7)Cl2] |
Zn/– |
16 |
0 |
|
11[c] |
[Ni(L8)Cl2] |
Zn/– |
16 |
5 |
|
12 |
[Ni(L5)Cl2] |
Zn/NaI |
2 |
95 (88) |
|
13 |
[Ni(L5)Cl2] |
Zn/– |
2 |
30 |
|
14[e] |
[Ni(L5)Cl2] |
Zn/NaI |
2 |
60 |
[a] All reactions were carried out under N2 in dry DMA ([1 a]: 0.2 M, 2: 3 eq., [H]: 2 eq., TMSCl: 1 eq.; additive: 1 eq., cat: 10 mol%, unless otherwise specified). [b] Determined by 19F NMR on the reaction crude with an internal standard (CF3C6H5). In brackets, isolated yields after flash chromatography. [c] The catalytic complex was prepared in situ (L/NiCl2 ⋅ glyme: 15/10 mol%). [d] Dehalogenative homocoupling of 1 a was determined as the major product. [e] With reagent grade DMA and under air. [H]: reductant. NR: no reaction. TMSCl: chlorotrimethylsilane.