The secondary metabolites that comprise the diterpenoid alkaloids are categorized into C₁₈, C₁₉, and C₂₀ families depending on the number of contiguous carbon atoms that constitute their central framework. Herein, we detail our efforts to prepare these molecules by chemical synthesis, including a photochemical approach, and ultimately a bioinspired strategy that has resulted in the development of a unifying synthesis of one C₁₈ (weisaconitine D), one C₁₉ (liljestrandinine), and three C₂₀ (cochlearenine, paniculamine, and N-ethyl-1α-hydroxy-17-veratroyldictyzine) natural products from a common intermediate.