The Use of 5-Halocyclooctenes as a Radical Probe. Reactions with Lithium Aluminum Hydride

Article abstract of DOI:10.1021/jo00369a009

The 5-halocyclooctenes have been studied as a radical probe in their reactions with lithium aluminum hydride (LiAlH4) in order to detect the occurrence of radical intermediates and also to evaluate the effectiveness of these compounds as radical probes.Also the 4-cyclooctenyl radical was trapped by dicyclohexylphosphine (DCPH), dicyclohexylphosphine deuteride (DCPD), and cyclohexadiene.For the iodide, and to a lesser extent the bromide, radical intermediates were found to be a major component in the reaction since the bicyclo hydrocarbon was the major product.No evidence for radical intermediates was found for reactions of the correspon ding chloride or tosylate with LiAlH4.It is concluded that 5-iodocyclooctene is an effective radical probe for those reactions where radical intermediates are involved