Highly Stereoselective Formal Synthesis of Rosuvastatin and Pitavastatin Through Julia-Kocienski Olefination Using the Lactonized Statin Side-Chain Precursor

An expedient and simple synthetic approach to pitavastatin and rosuvastatin final intermediates is described. The presented approach consists of completely stereoselective Julia-Kocienski olefination step (E/Z up to 300: 1) between lactonized statin side-chain precursor and sulfone derivative of the corresponding pyrimidine and quinoline heterocyclic cores. The desired O-TBS protected statin lactones were isolated in 66-71% yield and high >97% purity (HPLC).