AbstractThe first steps of a novel approach to the total synthesis of 9, 11‐dehydroestrone via tricyclo[3.3.0.02,8]octan‐3‐one (2) are described. One route involves a tandem‐type transformation of the key intermediate 3 (A‐CD unit) consisting of cyclopropane cleavage and ring B closure to afford C, 18‐bisnor‐13 α, 17 α‐estradiol derivatives. E.g. the 3‐methoxy‐9 ζ‐hydroxy‐17 α‐methanesulfonyloxy derivative (‐)‐6 has been synthesized in 8 steps and 10% overall yield from 1,3‐cyclohexadiene. As an alternative, the A‐CD type intermediate 4b has been prepared and could be used for a ring C enlargement prior to cyclization.