New Azepine-Furan Spirocyclic Structures in the Reaction of 4-Aroyl-1,2-dihydrobenzo[d]azepines and 2-Aroyl-4,5-dihydrophenanthreno[1,2-d]azepine with Formaldehyde

Abstract

4-Aroyl-1,2-dihydrobenzo[d]azepines, aswell as their phenanthro[1,2-d]azepine ketoanalogs, under the action of formaldehyde in the presence of acid-basecatalysts, can undergo diastereoselective transformation into spirocyclicsystems, containing two spiro-fused hetero rings – tetrahydroazepine andbifunctionalized tetrahydrofuran. This transformation is provided by acombination of azepine-azepine recyclization of substrates followed byspirocyclization of its products