Diastereoselective addition of organomagnesium reagents to 17 beta-TBDMS-dihydrotestosterone

Several alkylations of the C3-carbonyl of 17 beta-TBDMS-DHT (1) with Grigna rd reagents were performed to obtain a series of potential inhibitors of an drogen formation. It has been found that, depending on the nucleophilicity of the Grignard reagent used, there was a difference in the diastereoselect ivity. The stronger reagents proceeded preferentially through the equatoria l attack, while the weaker ones proceeded through the axial attack.