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Synthesis of α‐Acyloxynitrones and Reactivity towards Samarium Diiodide
Author(s) -
Racine Emilie,
Burchak Olga N.,
Py Sandrine
Publication year - 2016
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.201600478
Subject(s) - nitrone , umpolung , chemistry , samarium diiodide , samarium , electrophile , alkoxy group , stereochemistry , combinatorial chemistry , organic chemistry , medicinal chemistry , nucleophile , cycloaddition , catalysis , alkyl
Upon treatment of fructose‐derived nitrone 1 with samarium diiodide, with the aim of inducing its umpolung and coupling with electrophiles, an unexpected β‐elimination of the benzyloxy group at C‐1 was observed, yielding nitrone 2 . The mechanism and scope of this transformation were investigated, from nitrone 1 and from five other α‐alkoxy or α‐acyloxy nitrones. This paper describes the preparation of new nitrones 3 and 4 from d ‐fructose; their synthesis demonstrates that acyl‐protected nitrones can be prepared efficiently by intramolecular N ‐alkylation of sugar‐derived oximes, a strategy previously developed only for ether‐ or ketal‐protected cyclic nitrones. Nitrones 3 and 4 underwent fast β‐elimination upon treatment with SmI 2 . Contrastingly, no β‐elimination occurred with nitrones 5 – 7 , suggesting a specific behavior of endocyclic keto nitrones.