Affiliation: | 1. Institute of Organic Chemistry, University of Vienna, W?hringer Strasse 38, 1090 Vienna, Austria, Fax: (+43)?1‐4277‐9 521;2. Department of Biomolecular Structural Chemistry, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria, Fax: (+43)?1‐4277‐9 522 |