An investigation of the mechanism of single and double hydrogen atom transfer reactions in alkyl benzoates by the ortho effect

Single and double hydrogen atom transfers in reactions (1) and (2) in the mass spectra of ethyl benzoate, isopropyl benzoate, and isobutyl benzoate have been investigated with reference to the ortho effect: (1) [C 6 H 5 CO 2 R] + ⋅ → [C 6 H 5 CO 2 H] + ⋅ ( m/z 122) + (R‐H); (2) [C 6 H 5 CO 2 R] + ⋅ → [C 6 H 5 CO 2 H 2 ] + ( m/z 123) + · (R‐2H). It is demonstrated that the intermediate ion [C 6 H 5 CO 2 H 2 ] + has the protonated benzoic acid structure with the hydrogen atom on the carbonyl group.