ASYMMETRIC SYNTHESIS OF (2R,5S,7R)-2,7-DIMETHYL-1,6-DIOXASPIRO[4.4]NONANE

摘要

A short-enantioselective synthesis of (2R,5S,7R)-2,7-dimethyl-1,6-dioxaspiro[4,4]nonane is described via an enantioselective synthesis of(2S,8S,SR)-2,8-dihydroxy-5-(1,3-dioxolanyl)-1,9-(p-tolylsulfinyl)-nonane by stereoselective reduction of the corresponding diketo disulfoxide. The formation of the spiro carbon was stereocontrolled during a cyclization carried out under equilibrating conditions in the presence of ZnBr2. [References: 24]