1. Organic Synthesis, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B‐2020 Antwerp, Belgium, Fax: (+32)‐32‐653‐233; phone: (+32)‐32‐653‐205
2. Janssen Research & Development, a division of Janssen Pharmaceutica N.V., Turnhoutseweg 30, B‐2340, Beerse, Belgium