The mechanism of the loss of H₂ and H₂O from 1,4‐cyclohexanediol anion and related compounds

Losses of H 2 and H 2 O from the [M‐H] − alkoxide anions of 1,4‐cyclohexanediol formed in OH − negative chemical ionization were studied using synthetic deuterated analogues and labelling by hydrogen‐deuterium exchange between neutrals in the ion source prior to ionization. Simple 1,2‐H 2 elimination leading to an enolate ion does not occur, but stereospecific mechanisms are shown to give a ketolate intermediate daughter ion. Collisionally activated dissociation spectra of the resulting daughter ions are the same as those of the corresponding ions generated directly from ketols.