Enantiomeric quantification of amines by 1H and 13C NMR: First report of S-citronellal as chiral derivatization agent (CDA)

The possibility of determining enantiomeric excess (ee) in chiral compounds by nuclear magnetic resonance (NMR) was discovered half a century ago and remains an important strategy nowadays. One way to determine ee in chiral compounds is to obtain diastereoisomers by using chiral derivatization agents (CDAs). CDAs bearing an aldehyde function have helped to discriminate primary chiral amines through a reaction that promptly yields imines. To the best of our knowledge, acyclic terpenes displaying an aldehyde function like S-citronellal have not been used in this context yet. In this study, we obtained excellent accuracy when we quantified aliphatic and aromatic amines by 1H and 13C NMR using S-citronellal as CDA. This analytical method proved to be fast and useful to quantify primary chiral amines.