Selective and unusual fluoride ion complexation by a steroidal receptor using OH...F- and CH...F- interactions: a new motif for anion coordination?

[structure: see text] A novel cholaphane has been synthesized from a naturally occurring bile acid in just two steps. It has an ability to bind two fluoride ions selectively utilizing the glycolate motif in chloroform. This "inside-out" cyclodextrin analogue encapsulates fluoride through O-H...F(-) and C-H...F(-) interaction.