Synthesis of novel hybrid steroid dimers by BF3·Et2O-catalyzed aldol condensation of 2-formyl-estradiol diacetate and steroid sapogenins.

ABSTRACT

BF3·Et2O-catalyzed aldol condensation of steroid sapogenins with 2-formyl-estradiol diacetate afforded two novel classes of steroid dimers in which an estrogenic core is attached to the spirostanic side chain of an steroid sapogenin through an exocyclic double bond in position C-23, or through a spiro centre in C-22.