Published in

Elsevier, Tetrahedron: Asymmetry, 23(20), p. 2709-2714

DOI: 10.1016/j.tetasy.2009.11.003

Links

Tools

Export citation

Search in Google Scholar

Cinchona alkaloids as privileged chiral solvating agents for the enantiodiscrimination of N-protected aminoalkanephosphonates—a comparative NMR study

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Red circle
Postprint: archiving forbidden
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

A series of chiral amines of increasing structural complexity, such as 1-(1-naphthyl)ethylamine, ephedrine, quinine, quinidine, 9-O-tert-butylcarbamoylquinine, and 9-O-tert-butylcarbamoylquinidine were studied as chiral solvating agents for the enantiodifferentiation of N-benzyloxycarbonyl derivatives of 1-aminoalkanephosphonic and phosphinic acids by means of 31P NMR spectroscopy. Among the cinchona alkaloids, that induced the most significant chemical shift non-equivalences, non-substituted quinidine exhibited the best effectiveness, excellent for analytical purposes (for example Δδ=0.348 up to 1.008ppm for phosphinic acid analogs). The signal separation of the diionic phosphonic acid enantiomers could be further optimized by the addition of an excess of the solvating agents. The newly obtained results appeared better when compared to the data set previously reported for the same analytes with the application of cyclodextrins.