Elucidation of Racemization Process of Azaspirene Skeleton in Neutral Aqueous Media

Azaspirene
and related congeners, which possess various biological
activities, have a unique spirocyclic core structure. However, there
are few studies on the chemical properties of (−)-azaspirene,
despite the fact that it may provide important insights into unveiling
the biosynthetic pathway. Here, we report a nine-step chemical synthesis
of an azaspirene analogue with a new finding that the natural (−)-azaspirene
skeleton easily racemizes in neutral aqueous media.