Tin-Free Radical Cyclization Reactions Using the Persistent Radical Effect I am grateful to Prof. Dieter Seebach for generous financial support and to Prof. Hanns Fischer for helpful discussions. Dr. Sylvain Marque is acknowledged for conducting the ESR experiments, and Dr. Volker Gramlich for carrying out the X-ray analysis. I also thank Christian Wetter and Elisabeth Baier for conducting some experiments.
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Laboratorium für Organische Chemie Eidgenössische Technische Hochschule ETH-Zentrum, Universitätstrasse 16, 8092 Zürich (Switzerland).