Substrate scope of 3-homoacyl coumarins 2a.
| ||||
|---|---|---|---|---|
| Entry | R1/R2 | 3 | Yieldb (%) | drc |
| 1 | 6-Br/C6H5 (2a) | 3aa | 86 | >20 : 1 |
| 2 | 6-F/C6H5 (2b) | 3ab | 88 | >20 : 1 |
| 3 | 6-Cl/C6H5 (2c) | 3ac | 78 | >20 : 1 |
| 4 | 7-Cl/C6H5 (2d) | 3ad | 84 | >20 : 1 |
| 5 | 7-Br/C6H5 (2e) | 3ae | 86 | >20 : 1 |
| 6 | 6-Me/C6H5 (2f) | 3af | 87 | >20 : 1 |
| 7 | 6-OMe/C6H5 (2g) | 3ag | 94 | >20 : 1 |
| 8 | 7-Me/C6H5 (2h) | 3ah | 86 | >20 : 1 |
| 9 | 7-OMe/C6H5 (2i) | 3ai | 83 | >20 : 1 |
| 10 | H/C6H5 (2j) | 3aj | 83 | >20 : 1 |
| 11 | H/4-FC6H4 (2k) | 3ak | 90 | >20 : 1 |
| 12 | H/4-BrC6H4 (2l) | 3al | 92 | >20 : 1 |
| 13 | H/4-MeC6H4 (2m) | 3am | 80 | >20 : 1 |
a
Reactions were carried out with 1a (0.1 mmol), 2 (0.12 mmol), and DBU (20 mol%) in 2 mL of THF at rt for 12–48 h.
b
Isolated yields.
c
Determined by 1H NMR.