Determination of the Absolute Configuration of (-)-Mirtazapine by Vibrational Circular Dichroism

The absolute configuration of the (−)-enantiomer of mirtazapine was determined by means of vibrational circular dichroism (VCD). The observed VCD of (−)-mirtazapine showed excellent correlation with the calculated VCD of the (R)-enantiomer. This is in agreement with the absolute configuration as determined by independent synthesis starting from (R)-phenylglycine.