New stereoselective synthesis of 9-methyl-cis-decalin derivatives by double Michael reaction of 3,5-dimethyl-4-methylenecyclohex-2-enone and dimethyl 3-oxoglutarate; X-ray crystal and molecular structure of two of the products

Abstract

Double Michael reaction of 3-methyl-, 2,3-dimethyl-, and 3,5-dimethyl-4-methylenecyclohex-2-enone with dimethyl 3-oxoglutarate in dimethyl sulphoxide in the presence of potassium fluoride as a catalyst gave stereoselectively 9-methyl-, 1,9-dimethyl-, and 4,9-dimethyl-6,8-dimethoxycarbonyl-2,7-dioxo-cis-decalin, respectively.