1. School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA 30332 (USA)
2. Department of Chemistry, 710 North Pleasant St., University of Massachusetts Amherst, MA 01003 (USA)
3. Organisch‐Chemisches Institut, Ruprecht‐Karls‐Universität, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany), Fax: (+49) 6221548404