Abstract
The mass spectral retroDielsAlder‐reaction: 1,2,3,4‐tetrahydrocarbazole1,2,3,4‐Tetrahydrocarbazole undergoes a retroDielsAlder‐reaction under electron impact. C(2) and C(3) are eliminated as ethylene. This is shown by measuring the deuterated derivatives1a,1band1c. Furthermore the oxo‐1,2,3,4‐tetrahydrocarbazole derivatives3and4are investigated in respect to the mass spectral retroDielsAlderreaction too.