The synthesis of indolo- and pyrrolo[2,1-a]isoquinolines

The synthesis of fused isoquinolines from N-benzyl protected indoles and pyrroles is described. For example, treatment of t-butyl-2-(2-formyl-3,4-dihydro-1-naphthalenyl)-3-methyl-1H-indole-1-carboxylate with KOBut in DMF provided 14-methyl-8-phenylbenzo[h]indolo[2,1-a]isoquinoline in good yield. Analogous N-benzylpyrrole precursors could similarly be cyclized to give pyrrolo[2,1-a]isoquinolines.