Synthesis 2017; 49(10): 2138-2152
DOI: 10.1055/s-0036-1588791
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© Georg Thieme Verlag Stuttgart · New York

Allylic Azide Rearrangement in Tandem with Intramolecular Huisgen Cycloaddition for Iminosugar and Glycomimetic Synthesis: Functionalized Piperidine, Pyrrolidine, and Pyrrolotriazoles from d-Mannose

Rekha Chadda
School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland   Email: paul.v.murphy@nuigalway.ie
,
Patrick McArdle
School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland   Email: paul.v.murphy@nuigalway.ie
,
Paul V. Murphy*
School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland   Email: paul.v.murphy@nuigalway.ie
› Author Affiliations
Further Information

Publication History

Received: 21 March 2017

Accepted: 23 March 2017

Publication Date:
20 April 2017 (online)


Abstract

Intramolecular Huisgen azide-alkene cycloaddition reaction of 7-azido-hepta-1,5-diene-3,4-diols, prepared from methyl α-d-man­no­pyranoside, were carried out. Allylic azide rearrangement to secondary azides occurred in tandem with triazoline formation and this intermediate was then decomposed in the presence of nucleophilic reagents to give pyrrolidines, piperidines, or azepanes depending on whether cyclic constraint was incorporated or not, on diol stereochemistry and on the nucleophile. The tandem reaction worked best when aziridine formation from the triazoline was efficient, and this efficiency improved on removal of cyclic constraint. Proposals to account for the observed diastereoselectivities are provided. The allylic azide rearrangement in tandem with the intramolecular Huisgen azide-alkyne cycloaddition was also investigated from azidoheptaenyne diols and gave dihydropyrrolotriazoles. All reactions were diastereoselective, and this was high in some cases. Two X-ray crystal structural determinations, 13C NMR data, and 1D and 2D NOESY experiments were used for stereochemical assignments.

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