Stereochemistry of HOH and HOAc elimination from 1‐tetralol and 1‐acetoxytetralin radical cations

Water and acetic acid eliminations from 1‐tetralin radical cations have been shown previously to be highly regiospecific 1,4 processes. Utilizing deuterium labeling, high resolution peak ratio measurements and metastable ion defocusing techniques, the stereochemistry of these processes has been investigated. cis‐4‐d₁‐ and trans‐4‐d₁‐1‐Tetralol both lose HOH and DOH in appreciable amounts; similarly, both acetoxy derivatives lose HOAc and DOAc. These results are interpreted in terms of an ionic epimerization which operates in competition with a stereospecific 1,4 elimination mechanism. A hydrogen exchange process which occurs between the 4‐carbon and the oxygen atom situated on the 1‐carbon of 1‐tetralol has also been observed. This process accounts for observed H/D ratios in the ethene elimination reaction of various deuterium labeled 1‐tetralols.