Table 4.
Michael addition–cyclocondensation synthesis of 1H-pyridine 5 or α-pyrone 6.
 | |||
| Entry | Alkynone 3 | 1H-Pyridine 5a | α-Pyrone 6a |
| 1 | 3a (R1 = Ph, R2 = Ph) | 5a (R1 = Ph, R2 = Ph, 56%) | – |
| 2 | 3b (R1 = p-MeOC6H4, R2 = Ph) | – | 6b (R1 = p-MeOC6H4, R2 = Ph; 70%) |
| 3 | 3c (R1 = p-Me2NC6H4, R2 = Ph) | – | 6c (R1 = p-Me2NC6H4, R2 = Ph, 12%) |
| 4 | 3d (R1 = p-F3CC6H4, R2 = Ph) | 5b (R1 = p-F3CC6H4, R2 = Ph, 22%) | – |
| 5 | 3e (R1 = p-NCC6H4, R2 = Ph) | 5c (R1 = p-NCC6H4, R2 = Ph, 20%) | – |
| 6 | 3f (R1 = Ph, R2 = p-MeOC6H4) | – | 6d (R1 = Ph, R2 = p-MeOC6H4, 82%) |
| 7 | 3g (R1 = Ph, R2 = p-Me2NC6H4) | – | 6e (R1 = Ph, R2 = p-Me2NC6H4, 62%) |
| 8 | 3h (R1 = Ph, R2 = p-F3CC6H4) | 5d (R1 = Ph, R2 = p-F3CC6H4, 25%) | – |
| 9 | 3i (R1 = Ph, R2 = p-NCC6H4) | 5e (R1 = Ph, R2 = p-NCC6H4, 2%) | – |
| 10 | 3j (R1 = p-MeOC6H4, R2 = p-MeOC6H4) | – | 6f (R1 = p-MeOC6H4, R2 = p-MeOC6H4, 45%) |
| 11 | 3k (R1 = p-MeOC6H4, R2 = p-F3CC6H4) | 5f (R1 = p-MeOC6H4, R2 = p-F3CC6H4, 37%) | – |
| 12 | 3l (R1 = p-F3CC6H4, R2 = p-MeOC6H4) | 5g (R1 = p-F3CC6H4, R2 = p-MeOC6H4,, 40%) | – |
| 13 | 3m (R1 = p-F3CC6H4, R2 = p-Me2NC6H4) | – | 6g (R1 = p-F3CC6H4, R2 = p-Me2NC6H4, 71%) |
| 14 | 3n (R1 = 2-thienyl, R2 = Ph) | 5h (R1 = 2-thienyl, R2 = Ph, 51%) | – |
aAll yields refer to isolated and purified products.