Table 1.
Screening of reaction conditions.a
 | ||
|---|---|---|
| Entry | Changed conditions | Isolated yield |
| 1 | None | 99% |
| 2 | Toluene as solvent | Trace |
| 3 | DMSO as solvent | ND |
| 4 | MeOH as solvent | Trace |
| 5 | THF as solvent | Trace |
| 6 | DCM as solvent | Trace |
| 7 | DMF as solvent | 17% |
| 8 | EtOAc as solvent | Trace |
| 9 | 0.5 eq amine Donor | 56% |
| 10 | 1.5 eq amine Donor | 98% |
| 11 | 2.0 eq amine Donor | 97% |
| 12 | Tri-n-octylamine as Donor | 29% |
| 13 | DABCO as Donor | Trace |
| 14 | Et3N as Donor | 28% |
| 15 | DIPEA as Donor | Trace |
| 16 | NPh3 as Donor | Trace |
| 17 | 1,3-DNB as Acceptor | 34% |
| 18 | 1,4-DNB as Acceptor | 17% |
| 19 | No Light | ND |
| 20 | No Donor | ND |
| 21 | No Acceptor | ND |
| 22 | Under Ar | ND |
| 23 | Under Air | 69% |
| 24 | 600 uL H2O as additive | Trace |
aReaction conditions: 1a (0.5 mmol), amine donor (0.5 mmol), 1,2-DNB acceptor (0.025 mmol, 5 mol%) in solvent (4.0 mL) under blue LED irradiation and oxygen atmosphere (1 atm).