Table 1.
Reaction Optimizationa
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entry | [Ni] | ligand | yield (%)b |
1c | NiCl2·DME | ttbtpy | 68 |
2 | NiCl2·DME | ttbtpy | 75 |
3 | NiCl2·DME | tpy | 47 |
4 | NiCl2·DME | phen | 14 |
5 | NiCl2·DME | dtbbpy | 15 |
6 | NiCl2·DME | 1-bpp | 49 |
7 | NiCl2·6H2O | ttbtpy | 20 |
8 | Ni(acac)2·xH2O | ttbtpy | 81 |
9d | Ni(acac)2·xH2O | ttbtpy | 80 |
10 | none | ttbtpy | 3 |
11 | Ni(acac)2·xH2O | none | 9 |
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12 | NiCl2·DME | ttbtpy | 18 |
13 | NiCl2·DME | tpy | 68 |
14 | NiCl2·DME | 1-bpp | 83 |
Conditions: Pyridinium salt 1a (0.1 mmol), [Ni] (10 mol %), ligand (12 mol %), AlkZnBr (1.6 equiv), THF/DMA (2:1, 0.2 M), 60 °C, 16–22 h, unless noted otherwise.
Determined by 1H NMR spectroscopic analysis using 1,3,5-trimethoxybenzene as internal standard.
AlkZnBr (1.4 equiv).
5 mol % [Ni], 6 mol % ligand.