Table 8.
Use of Cyclopentanone in Aldol Reaction.a
| Entry | Aldehyde | Mol % (1) | Conditions | Yield | eeb | drc |
|---|---|---|---|---|---|---|
| 1d | 6 | 2 | neat, H2O (1 equiv), 15 h, rt | 87 | 77 (syn), 91 (anti) | 1.05:1 |
| 3 | 6 | 2 | neat, 24 h, rt | 63 | 73 (syn), 74 (anti) | 3.2:1 |
| 4 | 6 | 20 | DCE, H2O (1 equiv), 16 h, 4°C | 94 | 87 (syn), 95 (anti) | 1.35:1 |
| 5 | 6 | 20 | DCE/EtOH (99:1), 36 h, 4°C | 87 | 85 (syn), 92 (anti) | 2:1 |
| 6 | 16f | 20 | DCE, H2O (1 equiv), 48 h, 4°C | 51 | 81 (syn), 93 (anti) | 1.5:1 |
All reactions were performed at 2 M concentration of aldehyde in solution and was five equivalents of 22 unless otherwise noted.
Determined by chiral HPLC analysis.
Determined by 1H NMR analysis.
This reaction was performed with two equivalents of 22.