Library screening with different epoxides and nucleophiles was performed in glas vials using each 1 mL 50 mM Tris•SO4 buffer, pH 7.0 containing 200 µL CFE (100 µL in case of styrene oxide 3) of respective library variants as well as 20 mM epoxide (10 mM in case of trans-2,3heptene oxide 5) and 2 eq of nucleophile at 22 °C and 900 rpm. Samples were taken at different time points (2 and 24 h with epoxide 1 + azide and haloalcohol 2e; 24 h with epoxide 1+ cyanide; 10 min with epoxide 3 + azide; 30 min with epoxide 5+azide) and extracted with an equal volume of tert-buthylmethylether (TBME) containing 0.1% dodecane as internal standard. Organic phases were dried over MgSO4 and analyzed via achiral (conversion of 1 and 5) and chiral GC (enantiomeric excesses as well as conversion of 3). Temperature programs and retention times of substrates and products are listed in Table .