On the Unexpected Formation of [2.2.1]- and [2.1.1]Homotriblattanes.

A new class of polycyclic caged compounds, the [2.n.1]homotriblattanes, is described herein. These scaffolds are accessed through a concise, three-step sequence featuring an unexpected radical cyclization of α-bromocyclopropyl ketones. Their structures and stereochemical assignments were confirmed by a combination of 2D NMR and X-ray crystallography. DFT studies provide mechanistic insight into their formation and the side products formed en route. This study expands the known chemical space of polycyclic cages and offers a new entry point into highly complex 3-dimensional frameworks.