Difluoroboron Complexes as Versatile Precursors for Steroid Modification. Lumiestrone‐Based Steroid Derivatives: Synthesis and Structural Studies

Abstract

A preparation method for steroid‐based difluoroboron complexes has been developed using lumiestrone as a steroid example. Previously inaccessible lumiestrone‐based difluoroboron complexes annulated at positions 16 and 17 of the D ring have been prepared. Such difluoroboron complexes may have large synthetic potential for heterofunctionalization of steroids at the D ring. An application of a borylation mixture Ac2O‐BF3⋅OEt2 significantly simplify the preparation of steroid “dimers” bearing two estrone moieties connected at positions 2 and 2′ via a linker. Crystal structures of key representatives have been determined by X‐ray diffraction.