The enantiomers of tertiary amine oxides 3 show NMR spectral nonequivalence in the presence of (-)-(S)- or (+)-(R)-t-butylphenylphosphinothioic acid 4. It is observed even for the ε-methyl protons and is large enough to determine the ee values of 3 having long alkyl chains. The enantiomeric thioacids 4 induce also an extremely large magnetic nonequivalence of the geminal N-methylene protons in 3.
Chiral t-butylphenylphosphinothioic acid in NMR analysis of tertiary amine oxides with a stereogenic nitrogen atom / J. Drabowicz, B.Dudziński, M. Mikołajczyk, S. Colonna, N. Gaggero. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 8:13(1997), pp. 2267-2270. [10.1016/S0957-4166(97)00235-8]
Chiral t-butylphenylphosphinothioic acid in NMR analysis of tertiary amine oxides with a stereogenic nitrogen atom
S. ColonnaPenultimo
;N. GaggeroUltimo
1997
Abstract
The enantiomers of tertiary amine oxides 3 show NMR spectral nonequivalence in the presence of (-)-(S)- or (+)-(R)-t-butylphenylphosphinothioic acid 4. It is observed even for the ε-methyl protons and is large enough to determine the ee values of 3 having long alkyl chains. The enantiomeric thioacids 4 induce also an extremely large magnetic nonequivalence of the geminal N-methylene protons in 3.
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