1. Organic and Macromolecular Chemistry, OC3, The University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan, and Faculty of Pharmaceutical Sciences, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba 278-8510, Japan