Synthesis of Artificial HMG-CoA Reductase Inhibitors Based on the Olefination Strategy

Synthetic methods were studied for optically active 6-oxo-3,5-isopropylidenedioxyhexanoate esters (4), which could be used as a key precursor of various kinds of artificial analogs of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors. An enantiomer (+)-4 was prepared by asymmetric reduction of β,δ-diketo esters derived from the Taber’s alcohol or l-tartrate followed by a series of chemical transformations, and the desired enantiomer (−)-4 was prepared by the same asymmetric reduction starting from d-tartrate. The key intermediate (−)-4 was finally converted into a highly potent HMG-CoA reductase inhibitor, NK-104.