Optimization of the reaction conditions.
| ||||||
|---|---|---|---|---|---|---|
| Entry | Photocatalyst | Solvent | Amine | 2aa (%) | 1a′a (%) | 1aa (%) |
| 1 | Erythrosine B (EB) | DMSO | iPr2NEt | 78(83) | 5 | 10 |
| 2 | Eosin Y | DMSO | iPr2NEt | 50 | 18 | 0 |
| 3 | AQN-2-Cl | DMSO | iPr2NEt | 12 | 10 | 63 |
| 4 | EB | DMSO | Et3N | 51 | 26 | 22 |
| 5 | EB | DMSO | 1-Methyl imidazole | 11 | 15 | 74 |
| 6 | EB | DMSO | iPr2NH | 36 | 21 | 40 |
| 7 | EB | MeCN | iPr2NEt | 70 | 0 | 26 |
| 8 | EB | DMF | iPr2NEt | 18 | 15 | 18 |
| 9 | EB | CHCl3 | iPr2NEt | 0 | 79 | 14 |
a
Yields are determined by 1H NMR spectroscopy using 1,1,2,2-tetrachloroethane as an internal standard. The number in parentheses denotes isolated yield.