Table 4.
Optimization of reaction conditions for the reaction between 2a and 10a.
 | ||||||
|---|---|---|---|---|---|---|
| Entrya | Capsule | T (°C) | 2a/10a | Yield (%)b | 11a (%)c | 12a (%)c |
| 1 | No | 50°C | 1/1 | — | — | — |
| Yes | 38 | 34 | 4d | |||
| 2 | No | 50°C | 2/1 | — | — | — |
| Yes | 60 | 54 | 6 | |||
| 3 | No | 50°C | 4/1 | — | — | — |
| Yes | 97 | 87 | 10 | |||
| 4 | No | 25°C | 4/1 | — | — | — |
| Yes | 20 | 18 | 2d | |||
a
Reactions were performed on a 0.16 mmol scale using 2a (from 1 to 4 equiv.), 3a (1 equiv.), and capsule C (0.26 equiv.) in water saturated CDCl3 (1.1 mL) under stirring for 16 h.
b
Overall yield of all the isolated products.
c
Yields of the isolated products by chromatography on column.
d
The column gave an inseparable mixture with regioisomer and the yield was calculated by integration of the respective 1H-NMR signals of the regioisomers in the isolated fraction.