Reaction optimisation II: formation of tetrahydroindolizine 14.
| ||||||
|---|---|---|---|---|---|---|
| Entry | Solvent | Temp. | Yield (%) | dra | ermajb | erminb |
| 1 | CPME | r.t. | 88 | 75 : 25 | 93 : 7 | 81 : 19 |
| 2 | i-PrOAc | r.t. | 71 | 70 : 30 | 97 : 3 | 68 : 32 |
| 3 | CPME | −40 °C | 76 | 90 : 10 | 94 : 6 | 92 : 8 |
| 4 | i-PrOAc | −40 °C | 83 | 90 : 10 | 98 : 2 | 96 : 4 |
a
Determined by 1H and 19F NMR spectroscopic analysis of the crude reaction product mixture, with values rounded to nearest 5.
b
Determined by chiral stationary phase HPLC analysis. CPME = cyclopentyl methyl ether. DMAP = 4-(dimethylamino)pyridine.