Baker'syeastreduction of methyl 3-oxo-4-pentynoate gave the corresponding (S)-3-hydroxyester (80% e.e.), whereas its 5-trimethylsilyl derivative gave the (R)-enantiomer (82% e.e.). The (S)-alcohol was led to optically active t-butyl (3R,5S)-3,5-isopropylidenedioxy-6-heptynoate, a versatile synthetic intermediate of artificial HMG-CoA reductase inhibitors.