Electron Spin Resonance of Oxiranyl Radicals in Solution: Configurational Stabilities and Rearrangement Reactions

Several alkyl substituted oxiranyl radicals derived by hydrogen abstraction from oxiranes are observed in solution by ESR.‐spectroscopy. The ESR.‐spectra demonstrate that oxiranyl radicals have pyramidal configurations at the radical carbon atom and undergo inversion. Alkyl substituted oxiranyls rearrange by ring opening to α‐keto alkyl radicals. The rates of inversion decrease and the rates of rearrangement increase with alkyl substitution. The activation parameters of these processes are given for several cases and are related to radical structure. Line broadening effects caused by inversion allow the determination of relative signs of γ‐CH3‐coupling constants.