An efficient approach to 17-chloro-16(17) unsaturated D-homo antiproge
stins is described. The key steps of the synthesis are a ring-expansio
n via dichlorocarbene addition to a 17-silyl enol ether and a palladiu
m catalyzed coupling of an 11 beta-(4-aryltriflate) with tributyl(1-et
hoxyethenyl)stannane or diethyl(3-pyridinyl)borane. The new progestelo
ne antagonists were tested for their biological activities and compare
d to those of known antiprogestins.