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

Adrian E Samkian; Hanh T Nguyen; Christopher D Vanderwal; Brian M Stoltz

doi:10.1016/j.tetlet.2025.155591

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

Tetrahedron Lett. 2025 Jul 15:164:155591. doi: 10.1016/j.tetlet.2025.155591. Epub 2025 Apr 11.

Authors

Adrian E Samkian¹, Hanh T Nguyen², Christopher D Vanderwal^{2

3}, Brian M Stoltz¹

Affiliations

¹ Warren and Katharine Schlinger Laboratory of Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 101-20, Pasadena, California 91125, United States.
² Department of Chemistry, 1102 Natural Sciences II, University of California, Irvine, California 92697, United States.
³ Department of Pharmaceutical Sciences, 856 Health Sciences Road, Suite 5400, University of California, Irvine, California 92697, United States.

PMID: 40453693
PMCID: PMC12121957 (available on 2026-07-15)
DOI: 10.1016/j.tetlet.2025.155591

Abstract

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.

Keywords: Carene; Chiral building; Radical cascade; Ring; blocks; fragmentation; triblattane.

Abstract

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