| (a) Protecting group screening | |||||
|---|---|---|---|---|---|
| |||||
| Entry | PG | C b | eec (%) | s d | |
| (R)-1a-1 | (S)-3a-1 | ||||
| 1 | Me | 0 | — | — | — |
| 2 | Piv | 45 | 54 | 66 | 8 |
| 3 | Cbz | 20 | 21 | 85 | 14 |
a
Reaction conditions: rac-1a-1 (0.1 mmol), ethyl acrylate 2a (0.6 equiv.), Pd(OAc)2 (10 mol%), ligand (30 mol%), Ag2CO3 (2.0 equiv.), 2-Cl-BQ (0.3 equiv.), 1,2-DCE (1.0 mL), N2, 75 °C, 3 days.
b
Calculated conversion, C = eeSM/(eeSM + eePR).
c
Determined by chiral HPLC analysis.
d
Selectivity (s) = ln[(1 − C)(1 − eeSM)]/ln[(1 − C)(1 + eeSM)].
e
Olefin (2.0 equiv.) used.
f
Instead of 2a, methyl acrylate was used.
g
50 mol% 2-Cl-BQ was used.