Recent Advances in the Preparation of Enantiomerically Pure Hydroxylamines from Nitrones

Abstract

This review covers the recent advances in the synthesis of enantiomerically pure hydroxylamines employing nitrones as starting materials. Nucleophilic additions of organometallic reagents to nitrones are the most common way for introducing a hydroxyamino group into carbon skeletons with the concomitant formation of a new carbon-carbon bond. Addition of carbanions derived from enolates, cyanide or fluorinated derivatives allow the preparation of complex structures. Radical additions and, in particular samarium diiodide-mediated reductive coupling of nitrones with carbonyl compounds and α,β-unsaturated esters have also been considered. All these approaches provide efficient methods of preparation of enantiomerically pure hydroxylamienes that are valuable synthetic intermediates. KeywordsHydroxylamines; Nitrones; Organometallics; Mannich; Reductive coupling 2 Graphical Abstract 3

Aza‐Henry Reaction with Nitrones, an Under‐Explored Transformation

“…Nitrones such as 2 are conveniently prepared by oxidation of the corresponding amines and are often obtained as easy to handle and stable crystalline compounds . Furthermore, the highly polarized double bond of nitrones is responsible for their high electrophilic character and for their susceptibility to nucleophilic addition of organometallic reagents . Hence, nitrones have been used as key substrates in the synthesis of designingly functionalized iminosugars.…”