1. Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg im Breisgau, Germany
2. State Key Laboratory of Antiviral Drugs, Henan Normal University, Xinxiang, Henan 453007, P. R. China
3. Pingyuan Laboratory, Henan Normal University, Xinxiang, Henan 453007, P. R. China
4. College of Chemistry and Institute of Green Catalysis, Zhengzhou University, Zhengzhou 450001, P. R. China