Table 2.
Intramolecular reactions of azides with aldehydes.

| entry | compd | n | R1 | R2 | acid | Product (yield, %)
|
|
|---|---|---|---|---|---|---|---|
| 4 | 5 | ||||||
| 1 | 3g | 0 | H | C6H13 | TFA | - | - |
| 2 | 3g | 0 | H | C6H13 | TiCl4 | - | - |
| 3 | 3a | 1 | allyl | H | TFA | - | 63 |
| 4 | 3a | 1 | allyl | H | TiCl4 | - | 90 |
| 5 | 3b | 1 | benzyl | H | TFA | - | 77 |
| 6 | 3b | 1 | benzyl | H | TiCl4 | - | 94 |
| 7 | 3c | 2 | allyl | H | TFA | 60 | - |
| 8 | 3c | 2 | allyl | H | TiCl4 | 96 | - |
| 9 | 3d | 2 | benzyl | H | TFA | 68 | - |
| 10 | 3d | 2 | benzyl | H | TiCl4 | 85 | - |
| 11 | 3e | 3 | allyl | H | TFA | 53 | - |
| 12 | 3e | 3 | allyl | H | TiCl4 | 41 | - |
| 13 | 3f | 3 | benzyl | H | TFA | 71 | - |
| 14 | 3f | 3 | benzyl | H | TiCl4 | 49 | - |