Table 2. Optimization of HDO Conditionsa.
| entry | H2 (bar) | co-catalyst | solvent | yieldb (%) |
|---|---|---|---|---|
| 1 | 20 | La(OTf)3 | AcOH | tracesc |
| 2 | 20 | La(OTf)3 | AcOH | traces |
| 3 | 40 | La(OTf)3 | AcOH | 19 |
| 4 | 40 | La(OTf)3 | EtOAc | 56 |
| 5 | 40 | La(OTf)3 | EtOAc | 85d |
| 6 | 40 | Dy(OTf)3 | EtOAc | 94d |
| 7 | 40 | La(OTf)3 | AcOH | 23e |
| 8 | 40 | La(OTf)3 | EtOAc | 29e |
| 9 | 40 | Dy(OTf)3 | EtOAc | 36e,f |
| 10 | 40 | La(OTf)3 | neat | 48g |
a
Reaction conditions: compound 3 (2 mmol), Pd/C (1.6 mol %), La(OTf)3 (15 mol %), solvent (5 mL), H2 (20–40 bar), 200 °C, 24 h.
b
Detected by GC.
c
0.5 mol % Pd/C used.
d
6 mmol scale.
e
Crude rearrangement product is used as starting material; yield is calculated over two steps from 2 (in 10 mmol scale).
f
12 mmol scale.
g
Isolated yield; 19 mmol scale, Pd/C (1.6 mol %), La(OTf)3 (5 mol %).