REGIOSELECTIVE SYNTHESIS OF RING A POLYMETHYLATED STEROIDS IN THE ANDROSTANE SERIES
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 o