1. Kekulé Institute of Organic Chemistry and Biochemistry and the Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany, Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany, Department of Infection Biology Germany, Leibniz Institute for Natural Product Research and Infection Biology − Hans Knöll Institute, 07745 Jena, Germany, and Institute of Organic Chemistry, University of Würzburg, 97074 Würzburg, Germany