77764-74-0Relevant academic research and scientific papers
Intramolecular Cyclisations of Biphenyl-2-carboxyl Radicals: Evidence for a Π-State Aroyloxyl Radical
Glover, Stephen A.,Golding, Stephen L.,Goosen, Andre,McCleland, Cedric W.
, p. 842 - 848 (1981)
Biphenyl-2-carboxyl radicals generated by homolysis of acyl hypoiodites cyclise intramoleculary giving mainly δ-lactones through Ar2-6 cyclisation. 2'-Alkoxybiphenyl-2-carboxyl radicals do not give the expected Ar1-5 cyclisation product but undergo a homolytic ipso-substitution of the 2'-substituent.The phenanthrene-4-carboxyl radical gives 5H-phenanthropyran-5-one.Consideration of the molecular orbitals involved suggests that the biphenyl-2-carboxyl radicals are in the ?-ground state and have a higher energy, and, therefore, a less thermally accessible Σ-state than the corresponding amido-radicals.It is suggested that acyloxyl radicals which readily decarboxylate have either a Σ-ground state or a thermally accessible excited Σ-state.
