We synthesized a novel series of benzocycloalkene derivatives and evaluated their binding affinities to melatonin receptors. To control the spatial position of the amide group, one of the important pharmacophores, we incorporated an endo double bond, an exo double bond (E- and Z-configurations), and a chiral center (R-and S-configurations) at position 1. The indan derivatives with the S-configuration at position 1 were the most promising in terms of ...