Table 5.
Comparison of conditions for pyrroloindoline formation.
 | ||||||
|---|---|---|---|---|---|---|
| entry | conditions | R1, R2 | pdt | yielda (%) | drb | ee (%)c |
| 1d | 9a | Me, Me (2c) | 3k | 70 | 5:1 | 65/80 |
| 2e | 9f, 4Å MS | Me, Me (2c) | 3k | 58 | 8:1 | 87/85 |
| 3d | 9a | CF3, Bn (2a) | 3a | 86 | 4:1 | 94/91 |
| 4e | 9f, 4Å MS | CF3, Bn (2a) | 3a | 39 | 7:1 | 98/95 |
a
Isolated yield.
b
Determined by 1H NMR analysis of mixture.
c
Determined by chiral stationary phase SFC or HPLC.
d
Reaction run with 1.0 equiv acrylate, 1.2 equiv SnCl4.
e
Reaction run with 1.2 equiv acrylate, 1.0 equiv SnCl4.