Synthesis of sominone and its derivatives based on an RCM strategy: discovery of a novel anti-Alzheimer's disease medicine candidate "denosomin".

Synthesis of sominone was achieved starting from dehydroepiandrosterone on the basis of an RCM strategy for the construction of a delta-lactone side chain. This synthetic protocol was applied for the synthesis of several analogous derivatives including 1-deoxy-24-norsominone (denosomin), which was revealed to exhibit notable bioactivities for new antidementia chemotherapy, exceeding the original natural compound sominone.