1. Institut für Organische Chemie und NMR‐I Labor der Chemischen Institute, Technische Universität Braunschweig, Hagenring 30, D‐38106 Braunschweig, Germany
2. Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
3. Department of Chemistry, University of Victoria, Victoria, BC, Canada V8W 3P6