Table 2.
No | R1 | R2 | Yield, % | dr (R:S) |
---|---|---|---|---|
2a | OMe | OMe | 72 | 56:44 |
2b | OPh | OPh | 69 | 50:50 |
2c | OBn | OBn | 69 | 50:50 |
2d | OEt | Ph | 54 | 50:50 |
2e | Ph | Ph | 64 | 55:45 |
2f | P-(R,R)-TADDOL | 72 | 60:40 | |
2g A | P-(R,R)-TADDOL | 36 | 97:3 |
A single epimer obtained by the crystallization of 2f.