Enantiodifferentiation of the antitumor alkaloid crispine A using the NMR chiral solvating agents (R)- and (S)-BINOL

The use of (R)- and (S)-BINOL as chiral solvating agents (CSA) to determine the enantiomeric purity of the antitumor alkaloid crispine A was investigated. The formation of diasteromeric host–guest complexes between the CSA and (±)-crispine A 1 produced significant 1H NMR signal splitting which allowed the accurate and rapid determination of the enantiomeric composition in CDCl3 or C6D6 solution.

Graphical abstractH-7 signals in the 1H NMR spectra of a 93:7 sample of crispine A complexed with five equivalents of (S)-BINOL in CDCl3.Figure optionsDownload full-size imageDownload as PowerPoint slide