Table 1 Optimization of the reaction conditionsa.
| |||||||
|---|---|---|---|---|---|---|---|
Entry | Catalyst | Solvent | Time (h) | Conv (%) | Yield (%)b | e.e. (%)c | E/Z |
1 | (S)-A1 | DCM | 0.5 | 98 | 88 | −11 | 6:1 |
2 | (R)-A2 | DCM | 0.5 | 100 | 80 | 34 | 18:1 |
3 | (R)-A3 | DCM | 0.5 | 100 | 85 | 83 | 20:1 |
4 | (R)-A4 | DCM | 0.5 | 100 | 92 | 79 | >20:1 |
5 | (R)-B1 | DCM | 0.5 | 98 | 94 | 84 | >20:1 |
6 | (R)-B2 | DCM | 0.5 | 93 | 91 | 85 | >20:1 |
7 | (R)-C1 | DCM | 0.5 | 100 | 82 | −26 | 20:1 |
8 | (S)-C2 | DCM | 0.5 | 100 | 82 | 72 | 18:1 |
9 | (R)-C3 | DCM | 0.5 | 37 | 32 | −77 | 6:1 |
10 | (S)-C4 | DCM | 0.5 | 18 | 17 | 44 | 4:1 |
11 | (R)-B2 | DCE | 1 | 87 | 88 | 76 | >20:1 |
12 | (R)-B2 | EA | 1 | 24 | 26 | 86 | >20:1 |
13 | (R)-B2 | PhCl | 1 | 100 | 99 | 89 | >20:1 |
14d | (R)-B2 | PhCl | 6 | 100 | 99 | 96 | >20:1 |
- aReaction conditions: 1 (0.20 mmol), 2 (0.24 mmol), catalyst (0.02 mmol), solvent (0.5 mL), RT. bDetermined by 1H NMR spectrum of the crude mixture using 1,3,5-iPr3C6H3 as an internal standard. cDetermined by chiral HPLC.
- d−40 oC.
