Nuclear magnetic resonance spectra of Di-t-butylaryl carbinols

Abstract

The preparation and N.M.R. spectra of five title compounds, none of which were substituted at the aryl 2 or 6 positions, is described. Appreciable (ΔG* c ± 1 kcal/mol) barriers to rotation about the sp²-sp³ carbon-carbon bonds exist in this series and the hydroxyl oxygen atom is in the plane of the aryl ring in the energetically favoured conformers. Two unequally populated low energy conformers were identified in the title compounds carrying different substituents at the 3 and 5 positions of the phenyl ring. Some general aspects of the determination of activation parameters from variable-temperature N.M.R. spectra are discussed.