A new method for distinguishing between enantiomers and racemates and assignment of enantiomeric purity by means of solid-state NMR. Examples from oxazaphosphorinanes.
It is shown that enantiomers and racemates that have identical isotropic NMR chemical shift as well as anisotropic chemical-shift tensor parameters can be easily distinguished by means of the ODESSA (One Dimensional Exchange Spectroscopy by Sideband Alternation) technique. The method is based on the fact that the molecular symmetries and packing of enantiomers and racemates are usually significantly different. The power of the proposed approach is demonstrated by employing as model compounds P-chiral oxazaphosphorine derivatives, which are widely used in clinical oncology. Correlation of the amplitude of the ODESSA decay (AOD) with enantiomeric excess is also presented.
Potrzebowski
Marek J
MJ
Department of Structural Studies, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza, Łódź, Poland. marekpot@bilbo.cbmm.lodz.pl
Tadeusiak
Elzbieta
E
Misiura
Konrad
K
Ciesielski
Włodzimierz
W
Bujacz
Grzegorz
G
Tekely
Piotr
P