A stereoconvergent synthesis of (+)-4-demethoxydaunomycin

Sharpless kinetic asymmetric epoxidation on (±)-2-(l-hydroxyethyl)-5,8-dimethoxy-3,4-dihydronaphthalene (8) followed by LAH reduction gave R-2-(S-l-hydroxyethyl)-2hydroxy-5,8-dimethoxy-1,2,3,4-tetrahydronaphthalene and the undesired antipode. The former was converted to R-(-)-2-acetyl-2 hydroxy-5,8-dimethoxy-l,2,3,4-tetrahydronapthalenR-(-)-5],while the latter was epimerized and recycled. R-(-)-5 has been exploited for the synthesis of(+)-4-demethoxydaunomycin