Table 1.
entry | reagenta | solvent | additive | 9a:10ab | yield (%)c |
---|---|---|---|---|---|
1 | NaBH4 | MeOH | - | - | 0 |
2 | NaBH4 | THF | - | 1:5 | 93 |
3 | Bu4NBH4 | THF | - | 1:5 | 98 |
4 | Me4NBH(OAc)3 | benzene | AcOH | 3:1 | 95 |
5 | Me4NBH(OAc)3 | PhCF3 | AcOH | 5:1 | 95 |
6 | NaBH(OAc)3 | PhCF3 | AcOH | 10:1 | 95 |
See Supporting Information for detailed experimental procedures.
Determined by 1H NMR analysis of the crude reaction mixture.
Isolated after purification by silica gel chromatography.