Synthesis of the dibenzo[b,d]azepine skeleton via a catalyst-free ring expansion domino reaction.

In this article, a hitherto unreported catalyst-free ring expansion reaction of tetrahydroisoquinolines with o-alkynylarylaldehydes for the construction of the dibenzo[b,d]azepine skeleton is described. Using air as a "green" oxidant, some important biologically active dibenzo[b,d]azepines were produced with favorable functional group tolerance and a wide substrate scope. The synthetic potential was further confirmed by facile scale-up reactions and the synthesis of isoindoline derivatives. [ABSTRACT FROM AUTHOR]