Table 1 Optimization of the reaction conditionsa.
From: Reductive dearomative arylcarboxylation of indoles with CO2 via visible-light photoredox catalysis
| ||
|---|---|---|
Entry | Variation from standard conditions | Yieldb |
1 | None | 88% |
2 | Without CO2 | n.d. |
3 | Without light | n.d. |
4 | Without 4CzIPN | n.d. |
5 | Without DIPEA | Trace |
6 | Without Cs2CO3 | 55% |
7 | Ir[(dF(Me)ppy)2(dtbbpy)](PF6) instead of 4CzIPN | 78% |
8 | Ru(bpy)3(PF6)2 instead of 4CzIPN | 52% |
9 | Et3N instead of DIPEA | 75% |
10 | DIPEA (0.4 mmol, 2.0 equiv) | 75% |
11 | K2CO3 instead of Cs2CO3 | 71% |
12 | KOPiv instead of Cs2CO3 | 74% |
13 | DMF instead of DMSO | 75% |
14 | ArI 1’ instead of ArBr 1 | 77% |
15 | ArCl 1” instead of ArBr 1 | 20% |
