Table 1.
Photooxygenation of 1 to 13.
| Entry | Solvent | Light Source | Conversion Timea (isolated yield of 13) |
|---|---|---|---|
| 1 | MeOHb | ambient light | > 2 d (nd) |
| 2 | HFIPb | ambient light | 1 d (trace) |
| 3 | MeOHb | 23 W CFLc | 18 h (>80%) |
| 4 | MeOHd | 23 W CFLc | 23 h (85%) |
| 5 | MeOHe | 23 W CFLc | 2.5 d (77%) |
a
Monitored by HR LC/MS for disappearance of 1;
b
On a 7–8 mg scale of 1 at 1–1.1 mg/mL conc.;
c
Compact fluorescent lamp at a distance of 15 cm;
d
6.0 mg of 1 in 5.5 mL of MeOH;
e
32.5 mg of 1 in 30 mL of MeOH;
nd = not determined