Stereoselective reduction of delta-hydroxy beta-ketoesters to syndiol in achiral micellar system

摘要

A novel, efficient and stereo-selective process for synthesis of statin side chain, a key intermediate for statin type cholesterol lowering drugs such as Lipitor (atorvastatin) and Crestor (rosuvastatin) in achiral micellar media is reported. The key feature of this process is sodium borohydride reduction of delta-hydroxy beta-ketoester in achiral micellar system in 92% de, thereby avoiding metal chelation methods which employ triakylborane, titanium (IV) isopropoxide or cerium (III) chloride prior to reduction.