Enantioselective synthesis of a trans-ethenyl-hydrindene, a useful steroid CD-ring diene precursor

A highly efficient enantioselective synthesis of protected trans-hydrindenol diene 1 is described starting from the readily available Hajos–Parrish ketone. The reported methodology represents the most convenient route (10 steps, 31% overall yield) to both enantiomeric forms of a steroid (estrogenic) CD-ring diene precursor.