One-Pot Access to Dibenzodiazepines and 9-Arylacridines from a Cyclic Dienamine

A synthesis of dibenzodiazepines and 9-arylacridines was achieved by reacting cyclic 1-amino-1,3-butadienes─derived from Morita-Baylis-Hillman adducts, with acetylene dicarboxylates. The transformations to both heterocycles proceeded through a similar Diels-Alder-retro-Diels-Alder-cyclization sequence, which could also be implemented as a one-pot protocol. The method worked well over a range of dienamines to afford dibenzodiazepines and acridines in good yields.