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Direct Umpolung of Glycals and Related 2,3‐Unsaturated N ‐Acetylneuraminic Acid Derivatives Using Samarium Diiodide
Author(s) -
Le Tien Xuan,
Papin Caroline,
Doisneau Gilles,
Beau JeanMarie
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201402891
Subject(s) - umpolung , chemistry , dihydropyran , nucleophile , samarium , substituent , sialic acid , neuraminic acid , stereoselectivity , anomer , reagent , n acetylneuraminic acid , medicinal chemistry , organic chemistry , stereochemistry , catalysis , biochemistry
The umpolung of glycals with samarium diiodide offers a simple route to novel carbohydrate‐derived nucleophilic reagents in a single step using a readily available reductant. The corresponding allyl samarium reagent that arises from the hexose series reacts with ketones at the C3 position with high stereoselectivity; carbon–carbon bond formation takes place only anti to the substituent at the C4 position of the dihydropyran ring. For the sialic acid series, the completely regio‐ and stereoselective coupling process of the samarium reagent occurs at the anomeric carbon atom and provides a new approach to the α‐C‐glycosides of N ‐acetyl neuraminic acid.