A sequential one-pot protocol for the synthesis of indole-based peri-annulated polyheterocycles
using trifluoroacetic acid and a gold–silver combined catalyst system is described.
The reaction is thought to proceed via an imine formation–cationic π-cyclization–alkyne
activation–intramolecular hydroamination sequence to yield novel dihydrobenzo[6,7]indolo[3′,4′:3,4,5]azepino[2,1-a]isoquinolines in good yields.
Key words
polyheterocycles - alkyne - indole - annulation - Lewis acid - regioselective