Chemistry:Chiral shift reagent

From HandWiki

A chiral shift reagent is a reagent used in analytical chemistry for determining the optical purity of a sample. Some analytical techniques such as HPLC and NMR, in their most commons forms, cannot distinguish enantiomers within a sample, but can distinguish diastereomers. Therefore, converting a mixture of enantiomers to a corresponding mixture of diastereomers can allow analysis. One method involves the reaction of a chiral derivatizing agent (CDA) with a mixture of enantiomers to produce diastereomers via covalent attachment. One of the most common CDA is Mosher's acid.[1]

Another method involves non-covalent interactions. NMR shift reagents such as EuFOD, Pirkle's alcohol, and TRISPHAT take advantage of the formation of diastereomeric complexes between the shift reagent and the analytical sample.[2]

References

  1. Dale, James A; Dull, David L; Mosher, Harry S (1969). "α-Methoxy-α-trifluoromethylphenylacetic acid, a versatile reagent for the determination of enantiomeric composition of alcohols and amines". The Journal of Organic Chemistry 34 (9): 2543–2549. doi:10.1021/jo01261a013. 
  2. Sastri, V.S; Bünzli, Jean-Claude; Rao, V. Ramachandra; Rayudu, G.V.S; Perumareddi, J.R (2003). "Lanthanide Nmr Shift Reagents". Modern Aspects of Rare Earths and Their Complexes. pp. 779–843. doi:10.1016/B978-044451010-5/50024-9. ISBN 9780444510105.