Synthesis and biological activity of 17-chloro-16(17) unsaturated D-homo antiprogestins

An efficient approach to 17-chloro-16(17) unsaturated D-homo antiprogestins is described. The key steps of the synthesis are a ring-expansion via dichlorocarbene addition to a 17-silyl enol ether and a palladium catalyzed coupling of an 11 beta-(4-aryltriflate) with tributyl(1-ethoxyethenyl)stannane or diethyl(3-pyridinyl)-borane. The new progesterone antagonists were tested for their biological activities and compared to those of known antiprogestins.