Table 1.
Optimization of ortho-halogenation reaction. X =halide.
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Entry | Additive (equiv) | Hal | Solvent | T [8C] | Yield [%][a] |
1 | none | Br | PrCN | 80 | 50 |
2 | none | Br | PrCN | 100 | 65 |
3 | AcOH (50) | Br | PrCN | 80 | 15 |
4 | Cu(OAc)2 (1) | Br | PrCN | 100 | trace |
5 | PhI(OAc)2 (1.5) | Br | PrCN | 80 | 80 |
6 | PhI(OAc)2 (1.5) | Br | PrCN | 100 | 65 |
7 | PhI(OAc)2 (1.5) | Br | C2H4Cl2 | 60 | 85 |
8 | PhI(OAc)2 (1.5) | I | C2H4Cl2 | 65 | 95 |
9 | PhI(OAc)2 (1.5) | Cl | C2H4Cl2 | 65 | 42 |
Yield determined by NMR spectroscopy.