Aza-Piancatelli Cyclization as a Platform for the Preparation of Scaffolds of Natural Compounds: Application to the Total Synthesis of Bruceolline D

The aza-Piancatelli cyclization provides an expedient synthesis of 4-aminocyclopentenone building blocks that may be converted into aminocyclopentitols, which are heavily represented motifs among natural products. However, its use as a key step in total synthesis was still unprecedented. Here, we disclose our in-depth investigations regarding this reaction in order to access highly complex structures representing the core of some natural molecules. The applicability of the cyclization was highlighted by the 3-step total synthesis of bruceolline D. Thus, we anticipate that this work will lay the ground for further applications in total synthesis.