Synthesis, enantioseparation, and absolute configuration assignment of iminoflavans by chiral high‐performance liquid chromatography combined with online chiroptical detection.

Four racemic iminoflavan derivatives were synthesized by simple condensation at C‐4 position of flavanone. All new compounds were characterized by using ultraviolet‐visible, infrared, and nuclear magnetic resonance spectroscopic techniques. A chiral chromatographic analysis of racemic mixtures was performed by direct chiral high‐performance liquid chromatography using Chiralcel® OD‐H as chiral stationary phase, and online‐coupled with electronic circular dichroism detector. The correlation of experimental electronic circular dichroism traces with quantum chemical electronic circular dichroism calculations run with time‐dependent density functional theory made it possible to elucidate the absolute configuration for each enantiomer, and to establish the elution order. [ABSTRACT FROM AUTHOR]