Properly protected derivatives 14 and 20 of the common precursor 17β-hydroxy-1-methyl-5α- androst-1-en-3-one (13) have been transformed in a regioselective manner into highly methylated androsta-1, 4-diene-3, 17-dione derivatives 6–8. Access to the manifold of 1, 4- dimethylated derivatives was gained by methylation of the kinetic lithium dienolate derived from 20, while thiomethylation of 14, via the thermodynamic dienolate or an equivalent, ...
