Institution: | 1. Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (P.R. China), Fax: (+86)?21‐6416‐6128;2. Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032 (P.R. China) |