Table 1.
benzaldehyde substituent | product | diastereomeric ratio (cis/trans)a | yield (DCM)b | yield (CHCl3)c |
H | 7a | 1 : 3 | 49 | 56 |
2-OMe | 7b | 1 : 1 | 51 | 58 |
3-OMe | 7c | 1 : 3 | 30 | 36 |
4-OMe | 7d | 1 : 5 | 48 | 60 |
2-OPiv | 7e | 1 : 3 | 48 | 62 |
3-OPiv | 7f | 1 : 5 | 42 | 44 |
4-OPiv | 7g | 1 : 3 | 47 | 58 |
a: As deduced by analysis of 1H NMR spectra or after CC separation b: reflux; c: 20°C.