Electron impact studies. Part XCIV. Retro-Diels–Alder reaction in negative-ion mass spectrometry. Nitro-2H,4H-1,3- and -2,3-dihydro-1,4-benzodioxins

Abstract

The first examples of specific retro-Diels–Alder reactions occurring from negative ions are reported for nitro-2H,4H-1,3- and -2,3-dihydro-1,4-benzodioxins. The extent of the retro-reaction from the nitro-1,3-benzodioxins is dependent upon the position of the nitro-group relative to the oxygenated ring. The fragmentation of model compounds has been used in order to rationalise the mechanism(s) of the various rearrangement processes.