ESR - Evidence fcr a radical 1,5-hydrogen shift from oxygen to carbon

✍ Scribed by H. Itzel; H. Fischer

• Publisher: Elsevier Science
• Year: 1975
• Tongue: French
• Weight: 146 KB
• Volume: 16
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)71921-6

✦ Synopsis

Intramolecular l,%ydrogen shifts from carbon atoms to oxygen radical-centers are well known'), the Barton-reaction') being one of the examples. We wish to report the observation of an unusual intramolecular 1,5+ydrogen shift in the reverse direction, i.e. from oxygen to a carbon radical-center. The previously reported') reaction of tert.-butoxy radicals with substituted 1-cyclopropyl-carbinols was reinvestigated by FSR-spectroscopy . The primary substituted l-cyclopropyl-1-hydroxy-carbinyl radicals I undergo the cyclopropyl-homoallyl-resrrange-ment4) to the two isomers of substituted 3-buten-4-01 radicals cis-2 and trans-2 which are observable by ESR3). For temperatures T 2 -5O'C we also detect a-keto-radicals 2. They are formed by an intramolecular rearrsngeaent of cis-2 involving the 1,5-hydrogen shift. This rearrsngement was not observed for trsns-2 and was not found reversible.