Sensing Amine Chirality With ¹⁹F NMR

Amines are workhorse molecules in biological systems, and the amine motif is popular in pharmaceuticals and drug candidates. MIT chemists Timothy M. Swager and Yanchuan Zhao have just made it easier for researchers to detect and distinguish chiral amines. Their method makes use of palladium complexes equipped with fluorinated chiral pincer ligands (example shown). Because of the complexes’ chiral binding pockets, when they associate with amines, they produce distinct chemical shift signals for various amines that can be detected with ¹⁹F NMR spectroscopy (J. Am. Chem. Soc. 2015, DOI: 10.1021/jacs.5b00556). The technique offers chemists an easy way to determine the enantiomeric excess of chiral amines, which could speed development of amine-based drugs with chiral centers. The researchers also show that the complexes can simultaneously identify up to 12 different amines in solution. It even works for aliphatic amines, which can be tough to separate using chiral HPLC.