Direct Synthesis of Polycyclic Tropinones by a Condensation-[4+3]-Cycloaddition Cascade Reaction

A concise method of constructing polycyclic tropinone frameworks was developed. The single-step synthesis of polycyclic tropinone consists of an intramolecular (4+3) cycloaddition reaction of N-nosyl-pyrrole with oxyallyl cation that was generated in situ by an intermolecular condensation reaction of the nucleophilic functional groups on a tethered pyrrole with the aldehyde of 2-(silyloxy)-acrolein. This cascade reaction afforded various polycyclic tropinones including tri-, tetra-, and pentacyclic systems in high yields as single diastereomers.

This is the peer reviewed version of the following article: T. Okamoto, M. Shibata, S. Karanjit, A. Nakayama, M. Yoshida, K. Namba, Chem. Eur. J. 2018, 24, 9508, which has been published in final form at https://doi.org/10.1002/chem.201802011. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.