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- Title
Stereospecific Access to α‐ and β‐N‐Glycosylamine Derivatives by a Metal Free O‐to‐N [3,3]‐Sigmatropic Rearrangement.
- Authors
Pratesi, Debora; Mirabella, Stefania; Petrucci, Giulia; Matassini, Camilla; Faggi, Cristina; Cardona, Francesca; Goti, Andrea
- Abstract
Glycosylamine derivatives are biologically relevant compounds widespread in Nature, but the synthesis of this motif has been little addressed and its access with control of configuration at the anomeric carbon is challenging. Glycals substituted at C‐3 with a carbamate group undergo, upon dehydration, a prompt allyl cyanate to isocyanate rearrangement to the isomeric N‐glycosyl isocyanates, which can be conveniently trapped by one‐pot nucleophilic addition with alcohols or amines to afford N‐glycosyl carbamates and ureas, respectively. The rearrangement follows a [3,3]‐sigmatropic pericyclic mechanism as illustrated by the stereospecificity of the reaction, with nitrogen being delivered at the anomeric position to the same face from which the oxygen at C‐3 has departed. Thus, glucal and galactal give β‐N‐glycosides exclusively while allal furnishes α‐N‐glycosides. cis‐Dihydroxylation of the synthesized unsaturated N‐glycosides afford different 1‐aminosugars with good selectivity.Glycals substituted at C‐3 with a carbamate group undergo, upon dehydration, a prompt allyl cyanate to isocyanate rearrangement to the isomeric N‐glycosyl isocyanates, which give N‐glycosyl carbamates and ureas by one‐pot addition of alcohols or amines. The rearrangement occurs with complete stereoselectivity via a [3,3]‐sigmatropic mechanism, affording α‐ or β‐linked amines depending on the configuration at C‐3 of the carbohydrate.
- Publication
European Journal of Organic Chemistry, 2022, Vol 2022, Issue 38, p1
- ISSN
1434-193X
- Publication type
Article
- DOI
10.1002/ejoc.202200804