Aza-Prins Type Cyclisation of Vinyl Bis-Sulfide-Tethered Amines for the Collective Synthesis of Piperidine, Indolizidine and Isoindolone Natural Products

Abstract

Herein, we report a Brønsted acid-mediated inter- and intramolecular aza-Prins cyclisation of vinyl bis-sulfide substituted amines, providing an efficient and highly stereoselective approach to piperidine, indolizidine, and isoindolone frameworks. This methodology offers a concise and versatile platform for the rapid assembly of multiple piperidine alkaloids such as (±)-coniine, (±)-conmaculatin, (±)-anabasine and (–)-dihydropinidine as well as indolizidine alkaloids viz. δ-Coniceine, (±)-epi-indolizidine 167B, (±)-epi-indolizidine 209D, (±)-epi-indolizidine 223AB. Furthermore, the developed methodology is applied in the synthesis of valmerin core.