Table 1. Optimization of the Photoinduced Synthesis of β-Lactams.
entry | light source | solvent | 5 (equiv) | yield 6 (%)a |
---|---|---|---|---|
1 | 440 nm LED | ethyl acetate | 1.0 | 78 |
2 | 440 nm LED | toluene | 1.0 | 90 |
3 | 440 nm LED | acetonitrile | 1.0 | 51 |
4 | 440 nm LED | ethyl acetate | 1.2 | 86 (72b, 86c) |
5 | 525 nm LED | ethyl acetate | 1.2 | n.d. |
Yield determined by 1H NMR using durene as the internal standard;
Isolated yield.
Conducted on 1 mmol scale.