Table 1. Optimization of the Reaction Conditions.
| entry | deviation | 3 yield (%)a,b |
|---|---|---|
| 1 | none | 75 (72) |
| 2 | 1.5 equiv of 1 | 51 |
| 3 | 1.1 equiv of (TMS)3SiH | 60 |
| 4 | Ph3SiH instead of (TMS)3SiH | 20 |
| 5 | acetone in place of CH3CN | 67 |
| 6 | Vapourtec 365 nm 45 min | 74 |
| 7 | no I, II, 2,6-lutidine or (TMS)3SiH | |
| 8 | no light or no light at 60 °C |
a
1 (1.25 mmol), 2 (0.5 mmol), BP I (20 mol %), Ni II (5 mol %), 2,6-lutidine (0.55 mmol), (TMS)3SiH (0.75 mmol) at room temperature, 390 nm for 16 h.
b
NMR yields using trichloroethylene as an external standard. Yield of the isolated compound is given in parentheses.