The Reactions of 1-Adamantyl Radicals with Acetonitrile and Their Bearing on Oxidative Decomposition of 1,1'-Azoadamantane

Article abstract of DOI:10.1021/jo00389a031

1-Adamantyl radicals (Ad^.) have been generated photochemically from azo-1,1'-adamantane (AA) in acetonitrile (MeCN).Product analysis by GC accounted for 98percent of the Ad groups as a mixture of adamantane (AdH), 1,1'-biadamantane (AdAd), and the coupling product (5) of Ad(Me)C=N^. with solvent-derived ^.Ch2CN.The remaining 57percent of the ^.CH2CN groups thet could be found appeared as succinonitrile.Kinetic modeling of the product distribution shows that Ad^. abstracts hydrogen from MeCN roughly four times as fast as it adds to the nitrile carbon .In our previous work on the oxidative decomposition of AA in MeCN, induced by the thianthrenecation radical (Th^.+), very little AdH but significantly larger amounts of AdAd and AdCOMe were obtained.We propose, therefore, that virtually no free Ad^. is formed or survives oxidation in the oxidative decomposition of AA.Further, the AdAd found in the oxidative reaction cannot have come from the dimerization of free Ad^. but may have arisen, instead, from the biadamantane cation radical (AdAd^.+), formed within a solvent cage.