1. Department of Chemistry, State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China
2. School of Chemistry, University of Edinburgh, Edinburgh EH8 9LE, United Kingdom
3. Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, P. R. China