1. Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
2. Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
3. BioDuro-Sundia, No.233 North FuTe Rd., WaiGaoQiao Free Trade Zone, Shanghai, 200131, P.R. China
4. Pfizer Worldwide Research and Development, Eastern Point Road, Groton, Connecticut 06340, USA
5. Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
6. Institute of Organic Chemistry, University of Vienna, 1090 Vienna, Austria