1. Institute of Organic Chemistry, University of Regensburg, 93040 Regensburg, Germany, http://www‐oc.chemie.uni‐regensburg.de/koenig/index.php
2. Institute of Physical and Theoretical Chemistry, University of Regensburg, 93040 Regensburg, Germany
3. State Key Laboratory of Fine Chemicals, DUT‐KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT), Dalian 116012, P. R. China
4. Department of Chemistry, Royal Institute of Technology (KTH) 10044 Stockholm, Sweden