Synthesis of Silyl Enol and Silyl Dienol Ethers of 20-Oxosteroids: The Effect of β-Substituents

An efficient method to obtain regioselectively the title compounds is described. Experimental studies concerning the effect of β-substituents on the generation of β-substituted silyl enol ethers made feasible for the first time the isolation and identification of the products resulting from the unstable thermodynamic silyl enol ether.