Unified Synthesis of 2‐Isocyanoallopupukeanane and 9‐Isocyanopupukeanane through a “Contra‐biosynthetic” Rearrangement

Abstract

Herein, we describe our synthetic efforts toward the pupukeanane natural products, in which we have completed the first enantiospecific route to 2‐isocyanoallopupukeanane in 10 steps (formal synthesis), enabled by a key Pd‐mediated cyclization cascade. This subsequently facilitated an unprecedented bio‐inspired “contra‐biosynthetic” rearrangement, providing divergent access to 9‐isocyanopupukeanane in 15 steps (formal synthesis). Computational studies provide insight into the nature of this rearrangement.