1. Otto-Diels-Institute for Organic Chemistry, University of Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
2. University of Bremen, Institute for Organic and Analytical Chemistry, Leobener Str. 7, 28359 Bremen, Germany
3. University of Bremen, MAPEX Center for Materials and Processes, Bibliothekstr. 1, 28359 Bremen, Germany