... Helmut Quast* and Martina Witzel Institut fur Organische Chemie der Universitat Wurzburg, Am Hubland, W-8700 Wiirzburg ... Financial support by the Fonds der Chemischen Industrie, Frank- furt am Main, is gratefully acknowledged. E = C0,Me ... 1653- 1658. Liebigs Ann. Chem. ...