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Exploitation of Furanoid 5‐Azido‐3‐ C ‐Branched‐Chain Sugars Towards Highly Functionalized Nitrogen‐Containing Carbohydrate Derivatives
Author(s) -
Xavier Nuno M.,
Queneau Yves,
Rauter Amélia P.
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001119
Subject(s) - chemistry , butenolide , amine gas treating , isomerization , furanose , hydrolysis , ketone , sugar , lactone , azide , stereochemistry , carbohydrate , organic chemistry , ring (chemistry) , catalysis
The ability of easily accessed 1,2‐ O ‐protected 5‐azido‐3‐ C ‐(ethoxycarbonyl)methylenefuranoses to serve as precursors for the generation of imino sugar derivatives containing an α,β‐unsaturated lactone or ketone functionality has been investigated. A key aspect was the propensity of the corresponding deprotected δ‐amino α,β‐unsaturated esters to undergo 5‐aminofuranose/iminopyranose isomerization. Acid hydrolysis of the δ‐amino ( Z )‐α,β‐unsaturated ester followed by treatment with base led to a butenolide‐containing N ‐ethylformamide arising from a rearrangement of the imino‐sugar‐fused butenolide intermediate induced by the conjugated system. When carrying out the ring expansion step under neutral conditions, a 2‐keto imino sugar was obtained that was readily converted into a 1,2‐dihydropyridin‐3‐one by acetylation. Furthermore, reduction of the δ‐azido ( E )‐α,β‐unsaturated ester to the amine was followed by spontaneous intramolecular cyclization, providing the related furanose‐fused unsaturated δ‐lactam.