1. Center for Supramolecular Chemistry & Catalysis and Department of Chemistry College of Science Shanghai University 99 Shang-Da Road Shanghai 200444 China
2. Department of Organic Chemistry Arrhenius Laboratory Stockholm University 10691 Stockholm Sweden
3. Skaggs Institute for Chemical Biology and Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA