<p>Most molecules in chemistry and biology are chiral, leading to mirror-image variants, so-called enantiomers. However, although the selective chemical synthesis of molecules in which the stereogenicity arises from a carbon atom is well-established, enantioselective approaches to nitrogen-stereogenic molecules are much less common<sup><CitationRef AdditionalCitationIDS="CR2" CitationID="CR1">1</CitationRef>–<CitationRef CitationID="CR3">3</CitationRef></sup>, and in case of acyclic, <i>N</i>-stereogenic amines, even unknown, because of their rapid pyramidal inversion. Here we describe the catalytic asymmetric synthesis of stable, acyclic <i>N</i>-stereogenic amines by the addition of enol silanes to nitronium ions that ion pair to a confined chiral anion. In the produced so-called anomeric amines, the commonly observed isomerization is slowed down by two <i>N</i>-oxy-substituents, which hamper nitrogen inversion. The important stereogenicity-creating step challenges previously established stereochemical descriptors of enantiodifferentiation. Computational studies provide further insight into the origin of the observed stereocontrol. Our work opens up a new avenue to investigate the fascinating and previously underexplored chemistry of enantiopure anomeric amines.</p>

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The asymmetric synthesis of an acyclic N-stereogenic amine

  • Chendan Zhu,
  • Sayantani Das,
  • Marie Sophie Sterling,
  • Nobuya Tsuji,
  • Spencer J. Léger,
  • Frank Neese,
  • Chandra Kanta De,
  • Benjamin List

摘要

Most molecules in chemistry and biology are chiral, leading to mirror-image variants, so-called enantiomers. However, although the selective chemical synthesis of molecules in which the stereogenicity arises from a carbon atom is well-established, enantioselective approaches to nitrogen-stereogenic molecules are much less common13, and in case of acyclic, N-stereogenic amines, even unknown, because of their rapid pyramidal inversion. Here we describe the catalytic asymmetric synthesis of stable, acyclic N-stereogenic amines by the addition of enol silanes to nitronium ions that ion pair to a confined chiral anion. In the produced so-called anomeric amines, the commonly observed isomerization is slowed down by two N-oxy-substituents, which hamper nitrogen inversion. The important stereogenicity-creating step challenges previously established stereochemical descriptors of enantiodifferentiation. Computational studies provide further insight into the origin of the observed stereocontrol. Our work opens up a new avenue to investigate the fascinating and previously underexplored chemistry of enantiopure anomeric amines.