Table 1.
Catalyst optimization studies.[a]
 | |||||
|---|---|---|---|---|---|
| entry | catalyst (mol%) | Ecell (V) | electrolyte (equiv.) | other | yield (%)b |
| 1c | 13 (8) | 1.5 | LiClO4 (6) | CFL | 25 |
| 2 | 14 (10) | 1.5 | LiClO4 (6) | – | 60 |
| 3 | 14 (10) | 1.5 | LiClO4 (1) | – | 23 |
| 4 | 14 (10) | 1.5 | TBAPF6 (1) | – | 45 |
| 5 | 14 (10) | 1.5 | TBABF4 (1) | – | 60 |
| 6 | 14 (10) | 1.5 | TBABF4 (1) | CFL | 18 |
| 7 | 14 (10) | 1.5 | TBABF4 (1) | no light | 0 |
| 8 | 14 (10) | – | TBABF4 (1) | no current | 12 |
| 9 | 14 (10) | – | – | no current, no acid | 11 |
| 10 | – | 1.5 | TBABF4 (1) | no catalyst | 0 |
| 11 | 14 (10) | 1.0 | TBABF4 (1) | – | 32 |
| 12 | 14 (10) | 2.0 | TBABF4 (1) | – | 50 |
| 13 | 14 (20) | 1.5 | TBABF4 (1) | – | 75 |
| 14 | 14 (15)d | 1.5 | TBABF4 (1) | 75 (73)e | |
 | |||||
[a]
Reaction conditions: 11 (2.0 mmol, 5.0 equiv), 9 (0.4 mmol, 1.0 equiv), electrophotocatalyst (0.04 mmol, 0.1 equiv), MeCN (6.0 mL), AcOH (4.0 mmol, 10 equiv), TBABF4 (0.4 mmol, 1.0 equiv), N2, carbon felt anode, Pt cathode. Reactions performed under constant voltage conditions with irradiation for 24 h at rt.
[b]
Yields determined by 1H NMR.
[c]
2.0 ml 11 was used.
[d]
15% catalyst added in two portions, 36 h reaction time.
[e]
Yield of isolated product.