41. A Highly Stereoselective Synthesis of C(11)-Functionalized Aromatic Steroids by an Intramolecular Benzocyclobutene-Olefin -Cycloaddition. Preliminary Communication
    Oppolzer, W.; Petrzilka, M.; Bättig, K.
    Helv. Chim. Acta 1977, 60, 2964-2967

The racemic cis-anti-trans-steroids 9 to 11 have been synthesized in a highly stereoselective manner starting from 4-methoxybenzocyclobutene carboxylic acid via the key step 8 → 9. (cf. Scheme 2).

DOI : 10.1002/hlca.19770600849