Regioselective base-catalysed rearrangement of steroidal αβ-unsaturated epoxides
Abstract
Rearrangement of 5,10-epoxy-Δ9(11)-steroids in the presence of potassium t-butoxide or lithium dialkylamides occurs by proton abstraction at C-4 or C-12 depending on the nature of the base and the configuration of the epoxide.