In this study, the (<i>S</i>)-enantiomers of the aporphine alkaloids, nuciferine and roemerine, were prepared <i>via</i> a synthetic route involving catalytic asymmetric hydrogenation and both stereoisomers were evaluated <i>in vitro</i> for functional activity at human 5-HT<sub>2</sub> and adrenergic α<sub>1</sub> receptor subtypes using a transforming growth factor-α shedding assay. Both enantiomers of each of the compounds were found to act as antagonists at 5-HT<sub>2</sub> and α<sub>1</sub> receptors. (<i>R</i>)-roemerine was the most potent compound at 5-HT<sub>2A</sub> and 5-HT<sub>2C</sub> receptors (p<i>K</i><sub>b</sub> = 7.8-7.9) with good selectivity compared to (<i>S</i>)-roemerine at these two receptors and compared to its activity at 5-HT<sub>2B</sub>, α<sub>1A</sub>, α<sub>1B</sub> and α<sub>1D</sub> receptors.