Table 4.
Cyclizations of secondary radical precursor 25 to 26
entry | substrate | er | product | % yielda | er | % chirality transfer |
---|---|---|---|---|---|---|
1 | rac-25a | 50/50 | rac-26 | 95 | 50/50 | N/A |
2 | rac-25b | 50/50 | rac-26 | 97 | 50/50 | N/A |
3 | (+)-25a | 98/2 | (+)-26 | 98 | 98/2 | 100 |
4 | (−)-25a | 99/1 | (−)-26 | 96 | 98/2 | 99 |
5 | (+)-25b | 100/0 | (−)-26 | 98 | 99/1 | 99 |
6 | (−)-25b | 100/0 | (+)-26 | 97 | 99.5/0.5 | 99.5 |
Yield after isolation by column chromatography on 10% w/w KF/silica gel.