Table 1.
entry | base | Time | Yield | E:Z |
---|---|---|---|---|
1 | KHMDS | 15 h | 63% | 25:75 |
2 | NaHMDS | 15 h | 61% | 40:60 |
3 | LiHMDS | 7 d | 28% | >95:5 |
4 | NaH | 15 h | 72% | 54:46 |
5 | MesLi | 4 d | 20% | >95:5 |
6 | LiH | 7 d | 65% | 93:7 |
Enolate generated in THF at −78 °C, N-phenylbistriflimide added and warmed to and stirred (time: see table).