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Updated: May 25, 2026

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
Stereoselective multicomponent assembly of enantiopure oxazolopiperidines and -azepines
Nicolas Zill1, Angèle Schoenfelder, Nicolas Girard
1Faculté de Pharmacie, UMR 7200, CNRS-Université de Strasbourg, Laboratoire d'Innovation Thérapeutique 74, route du Rhin, F-67401, Illkirch, France.
Abstract:
A multicomponent reaction (MCR) based on a cyclohydrocarbonylation (CHC) driven by hydroformylation was set up toward the efficient diastereoselective preparation of oxazolopiperidines (4a-e) and -azepines (7a-d). The bicyclic oxazolidines were obtained from chiral N-alkenylamino alcohols via transient cyclic iminium intermediates that underwent an intramolecular cyclization from the appendant oxygen. On the basis of a series of different experimental conditions, the diastereocontrol observed during the formation of the oxazolidines is best explained by the stereoelectronic effect induced by an A(1,3)-strain in a common cyclic iminium intermediate (A). This new sequence is suitable for diversity oriented syntheses, allowing the preparation of enantiopure (S)- and (R)-coniceine in five steps from commercially available material.
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