A practical synthesis of 3-substituted Δ3,5(6)-Steroids as new potential 5α-reductase inhibitor

A new and practical synthetic approach to 3-substituted Δ3,5(6)-Steroids, as potential 5α-reductase inhibitor, is described. The key step involves Pd-catalyzed coupling reaction of steroid 3-enol 5H-3-oxo-octafluoropentanosulfonates. 3-Phenylacetylenyl substituted Δ3,5(6)-steroid 3g and 3-phosphate substituted Δ3,5(6)-steroid 3f in our synthesized compounds exhibited high 5α-reductase inhibitory activity in vitro assay.