1. Laboratory of Organic Chemistry ETH Zürich Vladimir-Prelog-Weg 3 8093 Zürich Switzerland
2. Scripps Institution of Oceanography University of California San Diego La Jolla CA 92093 USA
3. Skaggs School of Pharmacy and Pharmaceutical Sciences University of California San Diego La Jolla CA 92093 USA
4. University of Zurich Winterthurerstrasse 190 8057 Zürich Switzerland