The activities of various hydrosilanes in the asymmetric palladium-catalyzed tandem allylic alkylation of benzene-1,2-diol 1a with the (Z)-but-2-ene-1,4-diol derived allylic acetate 2a.
| |||
|---|---|---|---|
| Entrya | Silane | Yieldb (%) | 3a : 4ac |
| 1 | PMHS | 99% | 1 : 0.48 |
| 2 | Ph2SiH2 | 99% | 1 : 0.59 |
| 3 | MePhSiH2 | 99% | 0 : 1 |
| 4 | PhSiH3 | n.r | — |
| 5 | MePh2SiH | 87% | 1 : 0 |
a
Reaction conditions: 1a (0.25 mmol), 2a (1.4 eq.), Pd2(dba)3 (2.5 mol%), hydrosilane (3 eq.), Fei-Phos (5 mol%), N2, rt, 48 h.
b
Isolated yields after silica gel chromatography.
c
Determined from GC-MS analysis.