Atom transfer cyclization of simple hexenyl iodides. A caution on the use of alkenyl iodides as probes for the detection of single electron transfer processes

✍ Scribed by Dennis P. Curran; Dooseop Kim

• Book ID: 104219414
• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 291 KB
• Volume: 27
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85336-8

✦ Synopsis

The trialkyltin initiated isomerization of I-iodo-5-hexene to (iodomethyl)cyclopentane is reported. Rapid and reversible iodine atom transfer between alkyd radicals is the key chain transfer step. The results suggest an important caution in the use of hexenyl iodides as SETprobes: a good mechanism exists whereby the yield of rearranged products may be much greater than the amount of radicals produced by the reaction under study!

We have recently reported the development of a synthetically useful atom transfer cyclization reaction which involves the isomerization of an hexynyl iodide 1 to a cyclic vinyl iodide as summarized in equation 1 .2 After initiation to form the hexynyl radical 2, standard cyclization generates the vinyl radical 3. In the key chain transfer step, vinyl radical 3 abstracts an iodine atom from the starting iodide 1 to produce the cyclic vinyl iodide 4 and the hexynyl radical 2. Note that the iodine atom transfer is effectively irreversible due to the nature of the radicals involved and we were readily able to estimate that kt approaches the diffusion controlled limit. Since no