title: Direct formation of the steroid nucleus by a nonenzymic biogenetic-like cyclization. Preparation of the cyclization substrate.
mesh_terms: D003500:Cyclization; D008722:Methods; D008961:Models, Structural; D013237:Stereoisomerism; D013256:Steroids / Q000138:chemical synthesis*; D013329:Structure-Activity Relationship
chemical_list: D013256:Steroids