Synthesis of Intermediate Leading to Pravastatin – DMAP as Catalyst

                            (1)                                                                                                (2)

1. A solution of the epoxide (1) (1.30 g, 0.00156 mmol), DMAP (0.08 g), and (S)-(+)-2-methylbutyric andydride (1.3 mL) in pyridine (5 mL) is prepared.
2. The reaction mixture is stirred for 2 days at ambient temperature.
3. The reaction mixture is quenched by the addition of water (1 mL) and stirred for a further 15 min.  A mixture of hexane/ethyl acetate (4:1) (25 mL) is added, and the reaction mixture is washed with saturated potassium bicarbonate solution.  Chromatography of the crude product (eluent hexane/ethyl acetate 4:1) affords the 2-methylbutyrate ester (1.30 g, 89%) (2).