Synthesis of new 10β-propargylic and 11β-allenic steroidal spirolactones

Abstract As part of continuing studies on the synthesis of new, biologically interesting I Iβ-substituted steroidal spirolactones, we describe here the competition between 10β-propargylation and 11β-allenylation. Grignard addition of allenyl magnesium bromide to an appropriate 5,10-epoxy-9(11)-olefin provides 10β-propargylation or 11β-allenytation. The role of the catalytic effect of copper chloride and of the solvent is evaluated. Confirmation of the structural assignments of these new 3,3-ethylenethioxy-10β-propargyl (or IIβ-allenyl)-19-nor-17α-pregna-4,9-diene-21,17-carbolactones is reported.