Enantiomeric Self-Recognition: Cation-Templated Formation of Homochiral Isoguanosine Pentamers This research was sponsored by the Separations and Analysis Program, Chemical Sciences Division, Office of Basic Energy Sciences, U.S. Department of Energy. J.D. thanks the Dreyfus Foundation for a Teacher-Scholar Award. We thank Professors Giovanni Gottarelli and Steve Rokita for helpful discussions.