The stereoselective Michael addition of alcohols dihydro-2tj-pyran-2-one afforded high yields of a key chiral portion of compactin and mevinolin. to 6-tosyloxymethyl-5,6synthon for the lactone Compactin (1) mevinolin (2) and related compounds have been cholesterol levels in animal models and man and thus may provide prevention and treatment of coronary artery disease.' In recent shown to lower serum important tools in the years, these compounds have been the targets of an increasing number of synthetic efforts, yet their synthesis remains a formidable challenge.2 Introduction of the 4R,6R-lactone ring stereochemistry, which is required for biological activity, has proved the most problematic.3 Despite recent improvements in synthetic methodology for controlling 1,3-asymmetry, 4*5 most syntheses suffer from low overall yields, a large number of steps, and/or are achiral. An attractive chiral synthon, epoxide 3, has been described by Guindon.' His synthesis, however, was lengthy and suffered from low stereoselectivity. In this connection, we wish to report an efficient, high yielding, highly stereoselective synthesis of an analogous chiral synthon which should be suitable for the large scale preparation of these biologically important molecules. Additionally, we demonstrate its utility by conversion to a model inhibitor previously prepared by Clive II