The co-solvent screening for (Amano PS-IM)-catalyzed KR of rac-4 with vinyl acetate after 72 hours.
| |||||
|---|---|---|---|---|---|
| Entry | Co-solventa (log P)b | Conv.c (%) | eesd (%) | eepd (%) | E e |
| 1 | 1,4-Dioxane (−0.31) | <5 | N.D.f | N.D.f | N.D.f |
| 2 | CH3CN (0.17) | <5 | N.D.f | N.D.f | N.D.f |
| 3 | Acetone (0.20) | 23 | 29 | 95 | 52 |
| 4 | THF (0.40) | 31 | 39 | 88 | 23 |
| 5 | Vinyl acetate (0.54) | 56 | 74 | 93 | 22 |
| 6 | TBME (0.96) | 55 | >99 | 81 | 49 |
| 7 | tert-Amyl alcohol (1.09) | 54 | 97 | 83 | 45 |
| 8 | PhCH3 (2.52) | 54 | 97 | 84 | 48 |
a
Conditions: rac-4 50 mg, Amano PS-IM 25 mg, organic solvent 1 mL, vinyl acetate 54 mg, 58 μL (3 equiv.), 30 °C, 800 rpm (magnetic stirrer).
b
Logarithm of the partition coefficient of a given solvent between n-octanol and water according to ChemBioDraw Ultra 13.0 software indications.
c
Based on GC, for confirmation, the % conversion was calculated from the enantiomeric excess of the unreacted alcohol (ees) and the product (eep) according to the formula conv. = ees/(ees + eep).
d
Determined by chiral HPLC analysis.
e
Calculated according to Chen et al.,26 using the equation: E = {ln[(1 − conv.)(1 − ees)]}/{ln[(1 − conv.)(1 + ees)]}.
f
Not determined.