Hexadecane → N-(methoxycarbonyl)-4-keto-D-proline methyl ester

Participants

Reaction Steps

An aqueous solution (5.0 mL) containing 25 mM N-(methoxycarbonyl)-4-keto-Dproline methyl ester and 25 mM N-(methoxycarbonyl)-4-keto-L-proline methyl ester in 0.200M sodium acetate (pH 5.0) was mixed with 2.5 g of immobilized Candida antartica lipase fraction B (Boehringer Mannheim, CHIRAZYME® L-2, c.-f., C2, lyo.) at 25° C. The reaction mixture was analyzed after 31 h by mixing the entire reaction mixture with 5.0 mL of 20 mM hexadecane in dichloromethane for 10 minutes, which resulted in the complete extraction of the unreacted D- and L-isomers. The dichloromethane extract was then analyzed by chiral gas chromatography on a Chiraldex G-TA column (Advanced Separation Technologies, Inc., 50 m×0.32 mm ID) to determine the amounts of the unreacted D- and L-isomers. After 31 h, an 85% enantiomeric excess of N-(methoxycarbonyl)-4-keto-D-proline methyl ester was obtained at 41% conversion of the racemic mixture.

Provenance & Evidence