Table 1. Synthesis of Lactam Precursors 5.
| entry | R1 | R2 | R3 | yield 1a–f (%)a | yield 2a–f (%)a | yield 3a–f (%)a | yield 4a–f (%)a | yield 5a–f (%)a |
|---|---|---|---|---|---|---|---|---|
| 1 | H | H | H | 93 (1a) | 91 (2a) | 87 (3a) | 74 (4a) | 50 (5a) |
| 2 | H | F | H | 97 (1b) | 94 (2b) | 82 (3b) | 76 (4b) | 73 (5b) |
| 3 | H | H | F | 94 (1c) | 81 (2c) | 79 (3c) | 67 (4c) | 44 (5c) |
| 4 | H | H | MeO | 91 (1d) | 55 (2d) | 94 (3d) | 71 (4d) | 43 (5d) |
| 5 | H | H | Me | 94 (1e) | 92 (2e) | 92 (3e) | 60 (4e) | 67 (5e) |
| 6 | Me | H | H | 76 (1f) | 98 (2f) | 77 (3f) | 48 (4f) | 86 (5f) |
a
Yield of pure products after flash column chromatography purification.