1. W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
2. Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
3. Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44801, Germany