Organisms have evolved to produce various natural products from a common precursor as a means of maximizing the number of secondary metabolites, thus acquiring selectional advantages. By adopting nature's divergent biosynthetic strategy, we transformed (+)-catharanthine to various iboga and post-iboga alkaloids, including (-)-conodusine A, (+)-conodusines B and C, (-)-voatinggine, (-)-tabertinggine, and (+)-dippinine B. Well-orchestrated oxidations and reorganizations of catharanthine derivatives enabled chemical access to these natural products.