Electron impact induced water elimination from hydroxyamides. 2—N-acetyl- and N-benzoyl-4a-hydroxydecahydroquinoline and N-Methyl-4a-hydroxy-2-oxodecahydroquinoline

Electron impact induced water elimination from the metastable molecular ions of N-acetyl- and N-benzoyl-4a-hydroxydecahydroquinoline mainly follows a formal 1,2] elimination. The initiating and ratedetermining step in the reaction is the hydrogen rearrangement from C-8a onto the carbonyl group. The transferred hydrogen is subsequently lost, together with the hydroxyl group. The almost complete absence of H₂O loss from both diastereomers of N-methyl-4a-hydroxy-2-oxodecahydroquinoline confirms that the reaction can only proceed when the carbonyl group is able to function as ‘hydrogen carrier’ by occupying positions in the vicinity of both a hydrogen and the hydroxyl function.