Fluorination of steroid estrogens with Selectfluor®: Elucidation of regio- and stereoselectivity

•Reaction of estradiol and 8α-estradiol with Selectfluor® was perfomed.•Mostly the product of fluorination at C-10 was isolated.•Results for estradiol are completely different from those reported in literature.•The fluorination occurs stereoselectively.

Two steroid estrogens, natural estradiol and 8α-estradiol, were fluorinated using Selectfluor® in ionic liquid. Unexpectedly, mostly products of fluorination at position C-10 were isolated instead of corresponding fluorophenols, as it was reported previously. The reaction proceeds stereoselectively, yielding different stereoisomers for different types of the steroid skeleton. Stereoselectivity was proved by 1D/2D NMR experiments and X-ray analysis of obtained products. The obtained compounds are suitable intermediates for synthesis of various classes of estrogens.

Graphical abstractTwo steroid estrogens, natural estradiol and 8α-estradiol, were fluorinated using Selectfluor® in ionic liquid. Unexpectedly, mostly products of fluorination at position C-10 were isolated. The reaction proceeds stereoselectively, yielding different stereoisomers for different types of the steroid skeleton.Figure optionsDownload full-size imageDownload as PowerPoint slide