Synthesis of estradiol backbone mimics via the Stille reaction using copper(II) oxide as co-reagent

Sterically hindered biaryls and 2-phenylbenzo[b]thiophenes that can serve as templates for mimics of the estradiol backbone were prepared in modest to good yields by the Stille reaction using CuO as a co-reagent. Due to the neutral conditions applied in the Stille reaction, protection strategies were unnecessary for hydroxy containing coupling partners. Ligandless coupling conditions were also evaluated.